WorldWideScience

Sample records for proximal aortic stiffness

  1. Proximal aortic stiffness is related to left ventricular function and exercise capacity in patients with dilated cardiomyopathy.

    Science.gov (United States)

    Patrianakos, Alexandros P; Parthenakis, Fragiskos I; Karakitsos, Dimitrios; Nyktari, Eva; Vardas, Panos E

    2009-05-01

    Patients with heart failure (HF) show abnormal arterial stiffening. We examined 60 patients (52.1 +/- 12, 8 years) with non-ischaemic dilated cardiomyopathy (NIDC), New York Heart Association II-III, in sinus rhythm, left ventricular ejection fraction 30.1 +/- 8.6%, and 44 normals. All subjects underwent an echocardiographic study and a cardiopulmonary exercise test. We evaluated the segmental proximal aorta (AO) pulse wave velocity (PWV) in the region of aortic arch with a new echo-method: from the suprasternal view, the distance between ascending and descending AO was measured with two-dimensional ultrasound, and the aortic flow wave transit time (TT) was measured with pulsed-wave Doppler. Pulse wave velocity was calculated as aortic distance/TT. Patients showed increased PWV (7.4 +/- 2.9 vs. 4.8 +/- 1.1 m/s, P age, sex, and body mass) VO(2) (both P exercise capacity. The echocardiographic assessment of the regional aorta PWV seems to be clinically important.

  2. HIV infection and aortic stiffness.

    Science.gov (United States)

    Leite, Luisa Helena Maia; Cohen, Ariel; Boccara, Franck

    People living with human immunodeficiency virus (HIV) infection and receiving antiretroviral therapy now have the same life expectancy as the general population. However, they have a higher risk of atherosclerotic cardiovascular events because of a complex and polyfactorial vasculopathy, combining the effects of antiretroviral therapy, the HIV virus itself, immune activation, chronic inflammation and metabolic disturbances. Whether people living with HIV infection experience increased vascular aging compared with the general population remains controversial. To summarize current knowledge of the association between HIV infection and aortic stiffness as a marker of vascular aging. This review included 18 clinical studies in adult populations, published between 2009 and 2016, and identified on PubMed/MEDLINE or other databases. Search terms were aortic stiffness, arterial stiffness, vascular aging, pulse wave velocity and HIV. All 18 studies were observational, and compared groups infected (HIV+) and not infected (HIV-) with HIV. Ten studies (55%) reported no significant differences in aortic stiffness between HIV+ groups and age-matched HIV- control groups. The main reported determinants of aortic stiffness were age, blood pressure, smoking, metabolic syndrome and HIV-related variables, including CD4/CD8 ratio, current T-CD4 count < 200/mm 3 and nadir T-CD4+ count < 200/mm 3 . We found discordant results regarding whether HIV+ patients had increased aortic stiffness compared with HIV- controls. However, HIV-related conditions were associated with vascular health. This association has been confirmed in recent prospective studies. There is emerging evidence that HIV itself and immune activity affect vascular health and the large arteries. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  3. Nondiabetic Glucometabolic Status and Progression of Aortic Stiffness

    DEFF Research Database (Denmark)

    McEniery, Carmel M; Wilkinson, Ian B; Johansen, Nanna B

    2017-01-01

    OBJECTIVE Aortic stiffness is an important predictor of futuremorbidity andmortality. Diabetes is associated with increased aortic stiffness, but the importance of nondiabetic glucometabolic status for accelerated aortic stiffening is unclear. We tested the hypothesis that adverse glucometabolic ...

  4. Music decreases aortic stiffness and wave reflections.

    Science.gov (United States)

    Vlachopoulos, Charalambos; Aggelakas, Angelos; Ioakeimidis, Nikolaos; Xaplanteris, Panagiotis; Terentes-Printzios, Dimitrios; Abdelrasoul, Mahmoud; Lazaros, George; Tousoulis, Dimitris

    2015-05-01

    Music has been related to cardiovascular health and used as adjunct therapy in patients with cardiovascular disease. Aortic stiffness and wave reflections are predictors of cardiovascular risk. We investigated the short-term effect of classical and rock music on arterial stiffness and wave reflections. Twenty healthy individuals (22.5±2.5 years) were studied on three different occasions and listened to a 30-min music track compilation (classical, rock, or no music for the sham procedure). Both classical and rock music resulted in a decrease of carotid-femoral pulse wave velocity (PWV) immediately after the end of music listening (all pclassical or rock music in a more sustained way (nadir by 6.0% and 5.8%, respectively, at time zero post-music listening, all pmusic preference was taken into consideration, both classical and rock music had a more potent effect on PWV in classical aficionados (by 0.20 m/s, p=0.003 and 0.13 m/s, p=0.015, respectively), whereas there was no effect in rock aficionados (all p=NS). Regarding wave reflections, classical music led to a more potent response in classical aficionados (AIx decrease by 9.45%), whereas rock led to a more potent response to rock aficionados (by 10.7%, all pMusic, both classical and rock, decreases aortic stiffness and wave reflections. Effect on aortic stiffness lasts for as long as music is listened to, while classical music has a sustained effect on wave reflections. These findings may have important implications, extending the spectrum of lifestyle modifications that can ameliorate arterial function. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  5. Alcohol intake and aortic stiffness in young men and women

    NARCIS (Netherlands)

    Elzen, A.P. van den; Sierksma, A.; Oren, A.; Vos, L.E.; Witteman, J.C.; Grobbee, D.E.; Hendriks, H.F.; Uiterwaal, C.S.; Bots, M.L.

    2005-01-01

    Background: Moderate alcohol consumption has been shown to protect against cardiovascular disease. Aortic stiffness can be regarded as a marker of cardiovascular disease risk. Previously we have shown an inverse to J-shaped association between alcohol intake and aortic stiffness in middle-aged and

  6. Ivabradine on aortic stiffness in patients with heart failure.

    Science.gov (United States)

    Nar, Gokay; Inci, Sinan; Aksan, Gokhan; Demirelli, Selami; Soylu, Korhan; Yuksel, Serkan; Gulel, Okan; Icli, Atilla

    2015-04-01

    The aim of this study was to evaluate the effect of ivabradine treatment on aortic stiffness by measuring aortic elastic parameters in patients with heart failure (HF) receiving ivabradine treatment. The study included clinical patients who were diagnosed with HF (ejection fraction, <35%), had sinus rhythm and persistent symptoms despite full medical treatment. The study group consisted of patients with a heart rate greater than 70 beats per minute and the control group consisted of patients with a heart rate less than 70 beats per minute. Echocardiographic measurements were conducted and aortic strain, aortic distensibility, and aortic stiffness index were calculated. By the end of the twelfth month, a decrease was observed in the left ventricular end-diastolic and end-systolic volumes, whereas ejection fraction was increased (P < 0.001). When aortic elastic parameters were evaluated between the 2 groups, there was no significant difference regarding aortic strain, aortic distensibility, and aortic stiffness index at the time of enrollment and during the visit at 3 months. At the twelfth month visit, aortic strain (P < 0.001) and distensibility (P < 0.001) were significantly increased, whereas there was a significant decrease in the aortic stiffness index (P < 0.001). During the follow-up at 12 months, significant improvements were observed in the left ventricular functions and aortic elastic parameters along with decreased heart rate in patients with HF receiving ivabradine treatment. This outcome may indicate that ivabradine treatment may correct aortic stiffness and may reduce aortic stiffness after 1 year of follow-up.

  7. The focal adhesion: a regulated component of aortic stiffness.

    Directory of Open Access Journals (Sweden)

    Robert J Saphirstein

    Full Text Available Increased aortic stiffness is an acknowledged predictor and cause of cardiovascular disease. The sources and mechanisms of vascular stiffness are not well understood, although the extracellular matrix (ECM has been assumed to be a major component. We tested here the hypothesis that the focal adhesions (FAs connecting the cortical cytoskeleton of vascular smooth muscle cells (VSMCs to the matrix in the aortic wall are a component of aortic stiffness and that this component is dynamically regulated. First, we examined a model system in which magnetic tweezers could be used to monitor cellular cortical stiffness, serum-starved A7r5 aortic smooth muscle cells. Lysophosphatidic acid (LPA, an activator of myosin that increases cell contractility, increased cortical stiffness. A small molecule inhibitor of Src-dependent FA recycling, PP2, was found to significantly inhibit LPA-induced increases in cortical stiffness, as well as tension-induced increases in FA size. To directly test the applicability of these results to force and stiffness development at the level of vascular tissue, we monitored mouse aorta ring stiffness with small sinusoidal length oscillations during agonist-induced contraction. The alpha-agonist phenylephrine, which also increases myosin activation and contractility, increased tissue stress and stiffness in a PP2- and FAK inhibitor 14-attenuated manner. Subsequent phosphotyrosine screening and follow-up with phosphosite-specific antibodies confirmed that the effects of PP2 and FAK inhibitor 14 in vascular tissue involve FA proteins, including FAK, CAS, and paxillin. Thus, in the present study we identify, for the first time, the FA of the VSMC, in particular the FAK-Src signaling complex, as a significant subcellular regulator of aortic stiffness and stress.

  8. Nonsteroidal antiinflammatory drugs are associated with increased aortic stiffness

    Directory of Open Access Journals (Sweden)

    Martin Claridge

    2005-07-01

    Full Text Available Martin Claridge1, Simon Hobbs1, Clive Quick2, Nick Day3, Andrew Bradbury1, Teun Wilmink11Department of Vascular Surgery, University of Birmingham, Birmingham Heartlands Hospital Birmingham, UK; 2Department of Surgery, Hinchingbrooke Hospital, Huntingdon, UK; 3Department of Epidemiology and Biostatistics, University of Cambridge, Cambridge, UKObjectives: Nonsteroidal antiinflammatory drugs (NSAIDS have been shown to retard aneurysm growth in animal models. In vitro studies have shown an inhibitory effect of NSAIDS on matrix metalloproteinase-9, interleukin-1β, and IL-6 mediated arterial wall elastolysis. The aim of this study was to investigate the effects of NSAIDs on arterial stiffness, a surrogate marker of elastolysis.Methods: 447 subjects enrolled in a community-based abdominal aortic aneurysm (AAA screening program were assessed for age, blood pressure, smoking status, and drug history. Aortic diameter and stiffness were measured by M-Mode ultrasound. The concentration of the amino-terminal propeptide of type III procollagen was used as a proxy measurement of type III collagen turnover.Results: NSAID ingestion was significantly (p = 0.006 associated with increased aortic wall stiffness after adjusting for age, aortic diameter, blood pressure, and smoking status. No such effect was seen for β-blockers, calcium channel antagonists, nitrates, angiotensin-converting enzyme inhibitors, diuretics, or antiplatelet agents.Discussion: These novel data show that NSAIDS are associated with increased aortic stiffness, possibly through the effects of cytokine mediated elastolysis. This in turn may prevent aortic expansion and the development of AAA.Keywords: nonsteroidal antiinflammatory drugs, abdominal aortic aneurysm, aortic stiffness, elastolysis

  9. Weight reduction and aortic stiffness in obese children and adolescents

    DEFF Research Database (Denmark)

    Hvidt, K. N.; Olsen, M. H.; Ibsen, H.

    2015-01-01

    Little is known about the effect of weight reduction on aortic stiffness and especially so in the young. The present study investigates whether weight reduction influences aortic stiffness in obese children and adolescents. Carotid-femoral pulse wave velocity (cfPWV) and augmentation index at heart...... rate 75 (AIx@HR75) were measured in 72 obese patients aged 10-18 years at baseline and after 1-year of lifestyle intervention (follow-up). We found that although the degree of obesity decreased (Delta body mass index z-score: -0.24 +/- 0.45, P ....27 +/- 0.47 ms(-1), P obesity measures. No significant change...

  10. Aortic stiffness and microalbuminuria in patients with chronic obstructive pulmonary disease

    Directory of Open Access Journals (Sweden)

    Alaa Refaat

    2015-07-01

    Conclusions: COPD is associated with increased aortic stiffness. MAU is independently related to aortic stiffness in patients with COPD. Further studies are necessary to investigate whether MAU could be an effective biomarker of aortic stiffness and potential cardiovascular compromise in patients with COPD.

  11. Carotid and Aortic Stiffness in Patients with Heterozygous Familial Hypercholesterolemia.

    Directory of Open Access Journals (Sweden)

    Alexandra I Ershova

    Full Text Available The role of plasma cholesterol in impairing arterial function and elasticity remains unclear. We evaluated arterial stiffness, measured locally in the common carotid artery by high-resolution echo-tracking, and aortic stiffness, using carotid-femoral pulse wave velocity (PWV (the "gold-standard" measurement of arterial stiffness, in treatment-naive patients with heterozygous familial hypercholesterolemia (FH.The study included 66 patients with FH (10-66 years old and 57 first-degree relatives without FH (11-61 years old. Carotid-femoral PWV was determined by SphygmoCor (AtCor, Australia. The parameters of carotid stiffness β-index, Peterson elastic modulus and local PWV were assessed with regard to the common carotid artery at a distance of 1cm from the bifurcation (AlokaProsound Alpha7, Japan.FH patients showed significantly higher β-index (6.3(4.8-8.2 vs. 5.2(4.2-6.4, p = 0.005, Ep (78(53-111 kPa vs. 62(48-79 kPa, p = 0.006, local PWV (5.4(4.5-6.4 m/c vs. 4.7(4.2-5.4 m/c, p = 0.005, but comparable values of carotid-femoral PWV (6.76(7.0-7.92 m/c vs. 6.48(6.16-7.12 m/c, p = 0.138. Carotid arteries and the aorta stiffened with age in patients with FH, but after 30 years, carotid arteries stiffened more significantly than the aorta.Our study demonstrated that treatment-naive patients with FH had stiffer carotid arteries than their relatives, but showed no difference in aortic stiffness. We also found out that the rate of reduction of elasticity of the aorta and carotid arteries in FH patients varies: it is observed earlier in carotid arteries than in the aorta.

  12. Lower-extremity arterial stiffness vs. aortic stiffness in the general population.

    Science.gov (United States)

    Wohlfahrt, Peter; Krajčoviechová, Alena; Seidlerová, Jitka; Galovcová, Markéta; Bruthans, Jan; Filipovský, Jan; Laurent, Stéphane; Cífková, Renata

    2013-08-01

    While determinants of aortic pulse wave velocity (aPWV) are well known, much less is known about factors affecting lower-extremity pulse wave velocity (lePWV). Unlike aPWV, increased lePWV does not predict cardiovascular risk, but limits lower-extremity blood flow and is associated with increased left ventricular mass. The aim of this study was to compare the effect of cardiovascular risk factors on aPWV and lePWV. A total of 911 individuals from the Czech post-MONICA study (a randomly selected 1% representative population sample, mean age 54±13.5 years, 47% men) were examined. Pulse wave velocity was measured using the SphygmoCor device. Aging had a large effect on aPWV, but only a small effect on lePWV. After adjustment for covariates, we observed that hypertension, diabetes, chronic kidney disease and dyslipidemia were positively and significantly associated with aPWV. However, only hypertension had a significant effect on lePWV. Increased ankle systolic blood pressure was associated with increased aPWV independently of brachial blood pressure. Ankle systolic blood pressure was more closely related to aPWV than lePWV. Subjects with an ankle-brachial index lower lePWV compared with individuals with a normal ankle-brachial index. Lower-extremity arterial stiffness is affected by age and cardiovascular risk factors to a lesser extent than aortic stiffness. Increased ankle systolic blood pressure is linked not only to increased lower-extremity arterial stiffness, but also increased aortic stiffness. In subjects with a low ankle-brachial index, lower-extremity arterial stiffness is spuriously decreased.

  13. Assessment of aortic wall stiffness in patients with Familial Mediterranean Fever.

    Science.gov (United States)

    Tavil, Yusuf; Oztürk, Mehmet Akif; Ureten, Kemal; Sen, Nihat; Kaya, Mehmet Güngör; Cemri, Mustafa; Cengel, Atiye

    2008-05-01

    To evaluate aortic wall stiffness and its relation between the aortic stiffness and the left ventricular function in patients with Familial Mediterranean Fever (FMF). The study population was composed of 31 patients with FMF in attack-free period (12 men, 19 women; mean age: 36+/-7 years) and 27 healthy subjects (10 men, 17 women; mean age: 34+/-7 years) who had volunteered to participate. Aortic stiffness indices, aortic strain and distensibility, were calculated from the aortic diameters measured by echocardiography and blood pressure obtained by sphygmomanometry. There were significant differences between the control and the patient group in aortic strain (mean (SD), 7.23+/-2.14 versus 4.91+/-1.66%, p=0.01) and distensibility (4.02+/-1.42 versus 2.84+/-1.46, 10(-6)cm(2)dyn(-1), p=0.001). Although there was no correlation between the aortic stiffness parameters and the left ventricular function parameters, there were significant negative correlations between the disease duration and aortic strain index (r=-0.29, p<0.001), and between the disease duration and distensibility (r=-0.32, p<0.001). Aortic stiffness measurements were found abnormal in patients with FMF. We have also demonstrated that there were significant correlations between aortic stiffness parameters and disease duration.

  14. Thoracic endovascular aortic repair (TEVAR) in proximal (type A) aortic dissection: Ready for a broader application?

    Science.gov (United States)

    Nienaber, Christoph A; Sakalihasan, Natzi; Clough, Rachel E; Aboukoura, Mohamed; Mancuso, Enrico; Yeh, James S M; Defraigne, Jean-Olivier; Cheshire, Nick; Rosendahl, Ulrich Peter; Quarto, Cesare; Pepper, John

    2017-02-01

    Thoracic endovascular aortic repair (TEVAR) has demonstrated encouraging results and is gaining increasing acceptance as a treatment option for aortic aneurysms and dissections. Yet, its role in managing proximal aortic pathologies is unknown-this is important because in proximal (Stanford type A) aortic dissections, 10% to 30% are not accepted for surgery and 30% to 50% are technically amenable for TEVAR. We describe our case series of type A aortic dissections treated by using TEVAR. Between year 2009 and 2016, 12 patients with acute, subacute, or chronic type A aortic dissection with the proximal entry tear located between the coronaries and brachiocephalic artery were treated with TEVAR at 3 centers. Various stent-graft configurations were used to seal the proximal entry tear in the ascending aorta under rapid pacing. A total of 12 patients (9 male, 3 female), mean age 81 ± 7 years, EuroSCORE II 9.1 ± 4.5, underwent TEVAR for the treatment of type A aortic dissection. Procedural success was achieved in 11 of 12 patients (91.7%). There was 1 minor stroke and 1 intraprocedural death. No additional deaths were reported at 30 days. At 36 months, there were 4 further deaths (all from nonaortic causes). The mean survival of these 4 deceased was 23 months (range 15-36 months). Follow-up computed tomography demonstrated favorable aortic remodeling. TEVAR is feasible and reveals promising early results in selected patients with type A aortic dissection who are poor candidates for surgical repair. The current iteration of stent-graft technology, however, needs to be adapted to features specific to the ascending aorta. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  15. Concentric left ventricular remodeling and aortic stiffness: a comparison of obesity and hypertension.

    Science.gov (United States)

    Rider, Oliver J; Nethononda, Richard; Petersen, Steffen E; Francis, Jane M; Byrne, James P; Leeson, Paul; Clarke, Kieran; Neubauer, Stefan

    2013-09-10

    Increased thoracic ascending aortic stiffness is thought to contribute to concentric left ventricular hypertrophy and increased mortality, a pattern seen in hypertension. As such, aortic stiffness and increased left ventricular mass are candidates by which obesity increases cardiovascular risk. However, obesity is characterized predominantly by increased abdominal aortic stiffness and with eccentric left ventricular hypertrophy. We aimed to establish whether or not, in addition to these changes, there is also an element of concentric remodeling in obesity that was predicted by ascending aortic stiffness. 301 subjects underwent cardiovascular magnetic resonance imaging to measure regional aortic distensibility and left ventricular morphology. To compare obesity with hypertension, subjects were separated into groups by hypertensive status and body mass index. In comparison to normotensive subjects, hypertension was linked with concentric remodeling (a 17% increase in left ventricular mass:volume ratio (LVM:VR), (pObesity, in the absence of hypertension, was associated with elevated left ventricular mass when compared to normal weight normotensive subjects (by 27%, pobesity was, however, not correlated with ascending aortic distensibility when adjusted for mean arterial pressure (R=-0.14,pobesity there is a concentric element of hypertrophy that, unlike in hypertension, is not linked to increased ascending aortic stiffness. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  16. Aortic stiffness in lone atrial fibrillation: a novel risk factor for arrhythmia recurrence.

    Directory of Open Access Journals (Sweden)

    Dennis H Lau

    Full Text Available BACKGROUND: Recent community-based research has linked aortic stiffness to the development of atrial fibrillation. We posit that aortic stiffness contributes to adverse atrial remodeling leading to the persistence of atrial fibrillation following catheter ablation in lone atrial fibrillation patients, despite the absence of apparent structural heart disease. Here, we aim to evaluate aortic stiffness in lone atrial fibrillation patients and determine its association with arrhythmia recurrence following radio-frequency catheter ablation. METHODS: We studied 68 consecutive lone atrial fibrillation patients who underwent catheter ablation procedure for atrial fibrillation and 50 healthy age- and sex-matched community controls. We performed radial artery applanation tonometry to obtain central measures of aortic stiffness: pulse pressure, augmentation pressure and augmentation index. Following ablation, arrhythmia recurrence was monitored at months 3, 6, 9, 12 and 6 monthly thereafter. RESULTS: Compared to healthy controls, lone atrial fibrillation patients had significantly elevated peripheral pulse pressure, central pulse pressure, augmentation pressure and larger left atrial dimensions (all P<0.05. During a mean follow-up of 2.9±1.4 years, 38 of the 68 lone atrial fibrillation patients had atrial fibrillation recurrence after initial catheter ablation procedure. Neither blood pressure nor aortic stiffness indices differed between patients with and without atrial fibrillation recurrence. However, patients with highest levels (≥75(th percentile of peripheral pulse pressure, central pulse pressure and augmentation pressure had higher atrial fibrillation recurrence rates (all P<0.05. Only central aortic stiffness indices were associated with lower survival free from atrial fibrillation using Kaplan-Meier analysis. CONCLUSION: Aortic stiffness is an important risk factor in patients with lone atrial fibrillation and contributes to higher atrial

  17. Determinants of aortic stiffness: 16-year follow-up of the Whitehall II study.

    Directory of Open Access Journals (Sweden)

    Nanna B Johansen

    Full Text Available Aortic stiffness is a strong predictor of cardiovascular disease endpoints. Cross-sectional studies have shown associations of various cardiovascular risk factors with aortic pulse wave velocity, a measure of aortic stiffness, but the long-term impact of these factors on aortic stiffness is unknown.In 3,769 men and women from the Whitehall II cohort, a wide range of traditional and novel cardiovascular risk factors were determined at baseline (1991-1993 and aortic pulse wave velocity was measured at follow-up (2007-2009. The prospective associations between each baseline risk factor and aortic pulse wave velocity at follow-up were assessed through sex stratified linear regression analysis adjusted for relevant confounders. Missing data on baseline determinants were imputed using the Multivariate Imputation by Chained Equations.Among men, the strongest predictors were waist circumference, waist-hip ratio, heart rate and interleukin 1 receptor antagonist, and among women, adiponectin, triglycerides, pulse pressure and waist-hip ratio. The impact of 10 centimeter increase in waist circumference on aortic pulse wave velocity was twice as large for men compared with women (men: 0.40 m/s (95%-CI: 0.24;0.56; women: 0.17 m/s (95%-CI: -0.01;0.35, whereas the opposite was true for the impact of a two-fold increase in adiponectin (men: -0.30 m/s (95%-CI: -0.51;-0.10; women: 0.61 m/s (95%-CI: -0.86;-0.35.In this large prospective study, central obesity was a strong predictor of aortic stiffness. Additionally, heart rate in men and adiponectin in women predicted aortic pulse wave velocity suggesting that strategies to prevent aortic stiffening should be focused differently by sex.

  18. Carotid arterial stiffness as a surrogate for aortic stiffness: relationship between carotid artery pressure-strain elastic modulus and aortic pulse wave velocity.

    Science.gov (United States)

    Nagai, Y; Fleg, J L; Kemper, M K; Rywik, T M; Earley, C J; Metter, E J

    1999-02-01

    Common carotid arterial (CCA) stiffness can be assessed during carotid ultrasonography, but its association with aortic stiffness, a well-defined cardiovascular risk factor, has not been clarified. This study examines the relationship between CCA and aortic stiffness. CCA pressure-strain elastic modulus (Ep) and aortic pulse wave velocity (APWV) were evaluated in 110 healthy volunteers (age 56.2 +/- 14.6 y) by B-mode and Doppler ultrasonography. CCA Ep increased linearly with age and was higher in men than in women (model r2 = 0.50, p < 0.001). APWV increased quadratically with age (model r2 = 0.54, p < 0.001), similarly for women and men. Both CCA Ep and APWV were linearly associated with systolic blood pressure (BP) (r = 0.53 and 0.46, respectively) but not with diastolic BP. A linear relationship was found between CCA Ep and APWV (APWV = 194.7 + 5.67 x Ep [model r2 = 0.42, p < 0.001]). CCA Ep was associated with APWV (p < 0.001) independent of age, gender, and BP (model r2 = 0.62, p < 0.001), and the most parsimonious model to explain APWV included CCA Ep and age (APWV = 601.73 - 15.64 x age + 0.223 x age2 + 2.69 x Ep [model r2 = 0.60, p < 0.001]). Thus, CCA Ep is moderately associated with APWV. CCA stiffness as assessed by B-mode may be useful as a surrogate for aortic stiffness.

  19. The importance of accurate measurement of aortic stiffness in patients with chronic kidney disease and end-stage renal disease.

    Science.gov (United States)

    Adenwalla, Sherna F; Graham-Brown, Matthew P M; Leone, Francesca M T; Burton, James O; McCann, Gerry P

    2017-08-01

    Cardiovascular (CV) disease is the leading cause of death in chronic kidney disease (CKD) and end-stage renal disease (ESRD). A key driver in this pathology is increased aortic stiffness, which is a strong, independent predictor of CV mortality in this population. Aortic stiffening is a potentially modifiable biomarker of CV dysfunction and in risk stratification for patients with CKD and ESRD. Previous work has suggested that therapeutic modification of aortic stiffness may ameliorate CV mortality. Nevertheless, future clinical implementation relies on the ability to accurately and reliably quantify stiffness in renal disease. Pulse wave velocity (PWV) is an indirect measure of stiffness and is the accepted standard for non-invasive assessment of aortic stiffness. It has typically been measured using techniques such as applanation tonometry, which is easy to use but hindered by issues such as the inability to visualize the aorta. Advances in cardiac magnetic resonance imaging now allow direct measurement of stiffness, using aortic distensibility, in addition to PWV. These techniques allow measurement of aortic stiffness locally and are obtainable as part of a comprehensive, multiparametric CV assessment. The evidence cannot yet provide a definitive answer regarding which technique or parameter can be considered superior. This review discusses the advantages and limitations of non-invasive methods that have been used to assess aortic stiffness, the key studies that have assessed aortic stiffness in patients with renal disease and why these tools should be standardized for use in clinical trial work.

  20. Long-term results after proximal thoracic aortic redo surgery.

    Directory of Open Access Journals (Sweden)

    Martin Czerny

    Full Text Available OBJECTIVE: To evaluate early and mid-term results in patients undergoing proximal thoracic aortic redo surgery. METHODS: We analyzed 60 patients (median age 60 years, median logistic EuroSCORE 40 who underwent proximal thoracic aortic redo surgery between January 2005 and April 2012. Outcome and risk factors were analyzed. RESULTS: In hospital mortality was 13%, perioperative neurologic injury was 7%. Fifty percent of patients underwent redo surgery in an urgent or emergency setting. In 65%, partial or total arch replacement with or without conventional or frozen elephant trunk extension was performed. The preoperative logistic EuroSCORE I confirmed to be a reliable predictor of adverse outcome- (ROC 0.786, 95%CI 0.64-0.93 as did the new EuroSCORE II model: ROC 0.882 95%CI 0.78-0.98. Extensive individual logistic EuroSCORE I levels more than 67 showed an OR of 7.01, 95%CI 1.43-34.27. A EuroSCORE II larger than 28 showed an OR of 4.44 (95%CI 1.4-14.06. Multivariate logistic regression analysis identified a critical preoperative state (OR 7.96, 95%CI 1.51-38.79 but not advanced age (OR 2.46, 95%CI 0.48-12.66 as the strongest independent predictor of in-hospital mortality. Median follow-up was 23 months (1-52 months. One year and five year actuarial survival rates were 83% and 69% respectively. Freedom from reoperation during follow-up was 100%. CONCLUSIONS: Despite a substantial early attrition rate in patients presenting with a critical preoperative state, proximal thoracic aortic redo surgery provides excellent early and mid-term results. Higher EuroSCORE I and II levels and a critical preoperative state but not advanced age are independent predictors of in-hospital mortality. As a consequence, age alone should no longer be regarded as a contraindication for surgical treatment in this particular group of patients.

  1. Serum neutrophil gelatinase-associated lipocalin levels and aortic stiffness in noncritical coronary artery disease.

    Science.gov (United States)

    Soylu, Korhan; Nar, Gökay; Aksan, Gökhan; Gedikli, Ömer; İnci, Sinan; Yuksel, Serkan; Nar, Rukiye; İdil Soylu, Ayşegül; Gulel, Okan; Şahin, Mahmut

    2014-12-01

    The aim of this study was to establish the degree of aortic stiffness and levels of neutrophil gelatinase-associated lipocalin (NGAL) in patients with stable ischemic heart disease. Patients who were found to have stable, noncritical lesions on coronary angiography were included in the study [noncritical coronary artery disease (CAD)]. The control group consisted of those patients who had similar risk profiles and metabolic parameters without atherosclerosis on angiography. A total of 101 patients were included in the study of which 56 had noncritical CAD. Whereas the aortic strain (9.11 ± 3.4 vs. 14.01 ± 4.1%, p < 0.001) and aortic distensibility (3.98 ± 1.9 10(-6) cm(2)/dyn vs. 6.33 ± 2.3 10(-6) cm(2)/dyn, p < 0.001) were lower in the noncritical CAD group, the aortic stiffness index was higher (6.34 ± 3.9 vs. 3.37 ± 2.4, p < 0.001) as compared to controls. Serum NGAL levels were higher in the noncritical CAD group (79.29 ± 38.8 vs. 48.05 ± 21.4 ng/ml, p < 0.001). NGAL levels were negatively correlated with aortic strain (p < 0.01, r = 0.57) and distensibility (p < 0.001, r = 0.62), but positively correlated with the aortic stiffness index (p < 0.001, r = 0.72). We show that in patients with noncritical CAD, the degree of aortic stiffness and NGAL levels are higher. These markers can be used as tools for further risk stratification of patients with noncritical CAD.

  2. Cine-CMR partial voxel segmentation demonstrates increased aortic stiffness among patients with Marfan syndrome.

    Science.gov (United States)

    Singh, Parmanand; Almarzooq, Zaid; Codell, Noel C F; Wang, Yi; Roman, Mary J; Devereux, Richard B; Weinsaft, Jonathan W

    2017-04-01

    Standard cine-cardiac magnetic resonance (CMR) imaging is commonly used to evaluate cardiac structure, geometry and function. Prior studies have shown that automated segmentation via partial voxel interpolation (PVI) accurately quantifies phantom-based cardiac chamber volumes and necropsy left ventricular myocardial mass. Despite this, the applicability and usefulness of PVI in the determination of physiologic parameters of the aorta such as aortic stiffness has yet to be investigated. Routine CMR was conducted with a 1.5T (GE) scanner with pulse sequences similar to that of standard CMR (parameters: TR 3.4 msec, TE 1.14 msec, flip angle 60°, temporal resolution ~30-40 msec). Views were obtained in standard cardiac-oriented longitudinal or axial views (2, 3 and 4 chambers). Within non-dilated regions of the descending thoracic aorta, aortic area was quantified via a novel PVI automated process (LV-METRIC), which discerns relative amounts of blood pool in each voxel. Aortic stiffness, as calculated from brachial artery pulse pressure and aortic area at maximal and minimal dimensions, was evaluated in 60 total segments (one segment per patient). All segments were in the descending aorta and were not aneurysmal. Sixty patients in total were studied, including 50 that had genetically-related aortic disorder [35 bicuspid aortic valve (BAV), 15 Marfan syndrome (MFS)]. Ten normal controls without aortic disease were included for comparison purposes. All patients (n=60) had evaluable CMR images for assessment of the descending aorta with use of automated segmentation. Patients with BAV and MFS were similar to controls in age, systolic blood pressure, brachial artery pulse pressure, smoking status or hypercholesterolemia (all P=NS). There were more women (PMFS cohort compared to BAV and controls. Descending aortic area in either systole (maximal) or diastole (minimal) was similar among all three cohorts. However, change in aortic area (ΔArea) throughout the cardiac cycle

  3. Comparison of arterial stiffness and microcirculatory changes following abdominal aortic aneurysm grafting.

    LENUS (Irish Health Repository)

    Moloney, M A

    2012-02-01

    BACKGOUND: Abdominal aortic aneurysm (AAA) surgery provides a unique opportunity to study the impact of arterial stiffness on central haemodynamics, reflected in augmentation index (AI). The aneurysmal aorta is significantly stiffer than undilated age-matched aorta. AIM: We investigated whether replacement of an aneurysmal aorta with a compliant graft would result in a decrease in AI, which would thus decrease myocardial workload parameters. METHODS: Patients undergoing elective open or endovascular AAA repair were assessed with applanation tonometry and laser fluximetry pre-operatively, immediately and long-term post-operatively. RESULTS: Replacement of a small segment of abnormal conduit vessel resulted in improvements in AI, demonstrating that arterial stiffness can be surgically manipulated. CONCLUSIONS: These results reflect a decreased myocardial workload post-aortic grafting. This decrease in AI is important from a risk factor management perspective, and arterial stiffness should become a further recognised and screened for risk factor in patients with known aneurysmal disease.

  4. Comparison of arterial stiffness and microcirculatory changes following abdominal aortic aneurysm grafting.

    LENUS (Irish Health Repository)

    Moloney, M A

    2010-11-11

    BACKGOUND: Abdominal aortic aneurysm (AAA) surgery provides a unique opportunity to study the impact of arterial stiffness on central haemodynamics, reflected in augmentation index (AI). The aneurysmal aorta is significantly stiffer than undilated age-matched aorta. AIM: We investigated whether replacement of an aneurysmal aorta with a compliant graft would result in a decrease in AI, which would thus decrease myocardial workload parameters. METHODS: Patients undergoing elective open or endovascular AAA repair were assessed with applanation tonometry and laser fluximetry pre-operatively, immediately and long-term post-operatively. RESULTS: Replacement of a small segment of abnormal conduit vessel resulted in improvements in AI, demonstrating that arterial stiffness can be surgically manipulated. CONCLUSIONS: These results reflect a decreased myocardial workload post-aortic grafting. This decrease in AI is important from a risk factor management perspective, and arterial stiffness should become a further recognised and screened for risk factor in patients with known aneurysmal disease.

  5. Stacked proximal aortic cuffs: an "off-the-shelf" solution for treating focal thoracic aortic pathology.

    Science.gov (United States)

    Wolford, Heather Y; Surowiec, Scott M; Hsu, Jeffrey H; Rhodes, Jeffrey M; Singh, Michael J; Shortell, Cynthia K; Illig, Karl A; Green, Richard M; Waldman, David L; Davies, Mark G

    2005-10-01

    To report our early experience with the endovascular placement of stacked Zenith main body extensions (cuffs) in the treatment of focal thoracic aortic pathology in high-risk patients. Between January 2003 and May 2004, 6 patients (3 men; mean age 59 years, range 37-82) with focal aortic pathology underwent endovascular repair using stacked 30 and 32-mm-diameter Zenith main body extensions. The setting was a university tertiary referral center for vascular disease. Indication for treatment included 2 descending thoracic aneurysms and individual cases of traumatic thoracic tear, diverticulum of Kommerell, thoracic pseudoaneurysm, and aortoesophageal fistula. All procedures were performed successfully, with a mean of 3 cuffs used. The patient with an aortoesophageal fistula expired after successful cuff placement due to sequela of massive pretreatment hemorrhage; fistula coverage was confirmed at autopsy. There were no type I endoleaks. Morbidity included an occluded right subclavian artery from traumatic passage of the device through the artery. No left subclavian arteries were covered. No neurological deficits or paraplegia was observed. The cuffs were patent in all surviving patients at an average follow-up of 7 months (range 3-12). Computed tomography in all survivors confirmed adequate cuff placement, absence of endoleak, and lack of cuff migration. Based on this experience, the following technical recommendations are offered: (1) right subclavian cutdown when needed to reach a lesion beyond the range of the sheath, (2) Dacron chimney placement, (3) stiff guidewire usage, (4) wire placement from the right subclavian artery through the common femoral artery if necessary to ease a sharp bend in the arch, and (5) cuff overlap of 25% to 50%. In high-risk patients, focal aortic pathology can be successfully treated with off-the-shelf commercially available cuffs using a stacking technique with acceptable mortality, morbidity, and short-term durability.

  6. Aortic stiffness is associated with white matter integrity in patients with type 1 diabetes

    Energy Technology Data Exchange (ETDEWEB)

    Tjeerdema, Nathanja; Schinkel, Linda D. van [Leiden University Medical Center, Department of Endocrinology and General Internal Medicine (C7-Q), Albinusdreef 2, PO Box 9600, Leiden (Netherlands); Westenberg, Jos J.; Elderen, Saskia G. van; Buchem, Mark A. van; Grond, Jeroen van der; Roos, Albert de [Leiden University Medical Center, Department of Radiology, Leiden (Netherlands); Smit, Johannes W. [Leiden University Medical Center, Department of Endocrinology and General Internal Medicine (C7-Q), Albinusdreef 2, PO Box 9600, Leiden (Netherlands); University Medical Center Nijmegen, Department of General Internal Medicine, Nijmegen (Netherlands)

    2014-09-15

    To assess the association between aortic pulse wave velocity (PWV) as a marker of arterial stiffness and diffusion tensor imaging of brain white matter integrity in patients with type 1 diabetes using advanced magnetic resonance imaging (MRI) technology. Forty-one patients with type 1 diabetes (23 men, mean age 44 ± 12 years, mean diabetes duration 24 ± 13 years) were included. Aortic PWV was assessed using through-plane velocity-encoded MRI. Brain diffusion tensor imaging (DTI) measurements were performed on 3-T MRI. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were calculated for white and grey matter integrity. Pearson correlation and multivariable linear regression analyses including cardiovascular risk factors as covariates were assessed. Multivariable linear regression analyses revealed that aortic PWV is independently associated with white matter integrity FA (β = -0.777, p = 0.008) in patients with type 1 diabetes. This effect was independent of age, gender, mean arterial pressure, body mass index, smoking, duration of diabetes and glycated haemoglobin levels. Aortic PWV was not significantly related to grey matter integrity. Our data suggest that aortic stiffness is independently associated with reduced white matter integrity in patients with type 1 diabetes. (orig.)

  7. Beneficial effects of low-dose aspirin on aortic stiffness in hypertensive patients.

    Science.gov (United States)

    Pietri, Panagiota; Vlachopoulos, Charalambos; Terentes-Printzios, Dimitris; Xaplanteris, Panagiotis; Aznaouridis, Konstantinos; Petrocheilou, Katerina; Stefanadis, Christodoulos

    2014-12-01

    While treatment with low-dose aspirin has been established as a therapeutic tool for secondary prevention, the role of aspirin on primary prevention remains controversial. Aortic stiffness and wave reflections are independent predictors of cardiovascular events. The aim of the present study was to investigate the effect of low-dose aspirin on aortic stiffness and wave reflections in hypertensive patients. We studied 30 patients with grade I hypertension. Fifteen patients were treated with 160 mg of aspirin and 15 patients with placebo. Aortic stiffness and wave reflections were assessed by measuring carotid-femoral pulse wave velocity (PWV) and heart rate-adjusted augmentation index (AIx75), respectively. All measurements were conducted at baseline and 2 weeks after treatment. In the aspirin group, there was a significant reduction in PWV compared to the placebo group (from 8.9±1.5 to 8.5±1.6 m/s for the aspirin group vs from 8.6±1.4 to 8.7±1.6 m/s for the placebo group, net change: -0.5 m/s; p=0.02). AIx75 showed a marginal decrease (from 28.0±5.4 to 26.2±5.0% for the aspirin group vs from 31.2±9.7 to 30.6±9.2% for the placebo group, net change: -1.2%; p=0.06). In conclusion, a 2-week course of aspirin administration has a favorable effect on aortic stiffness and, to a lesser extent, on wave reflections in hypertensive patients. Whether the reduction in arterial stiffness is translated to fewer cardiovascular events needs to be confirmed by future prospective studies. © The Author(s) 2014.

  8. Mechanisms of Improved Aortic Stiffness by Arotinolol in Spontaneously Hypertensive Rats

    OpenAIRE

    Zhou, Wugang; Hong, Mona; Zhang, Ke; Chen, Dongrui; Han, Weiqing; Shen, Weili; Zhu, Dingliang; Gao, Pingjin

    2014-01-01

    OBJECTIVES: This study investigates the effects on aortic stiffness and vasodilation by arotinolol and the underlying mechanisms in spontaneously hypertensive rats (SHR). METHODS: The vasodilations of rat aortas, renal and mesenteric arteries were evaluated by isometric force recording. Nitric oxide (NO) was measured in human aortic endothelial cells (HAECs) by fluorescent probes. Sixteen-week old SHRs were treated with metoprolol (200 mg·kg-1·d⁻¹), arotinolol (30 mg·kg-1·d⁻¹) for 8 weeks. Ce...

  9. Left Atrial Mechanical Function and Aortic Stiffness in Middle-aged Patients with the First Episode of Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Alev Kilicgedik

    2017-01-01

    Conclusion: The association between aortic stiffness with reduced atrial strain and the key role of AoPP in the development of AF should be considered when treating nonvalvular AF patients with normal LA sizes.

  10. Telemetric ambulatory arterial stiffness index, a predictor of cardio-cerebro-vascular mortality, is associated with aortic stiffness-determining factors.

    Science.gov (United States)

    Li, Zhi-Yong; Xu, Tian-Ying; Zhang, Sai-Long; Zhou, Xiao-Ming; Xu, Xue-Wen; Guan, Yun-Feng; Lo, Ming; Miao, Chao-Yu

    2013-09-01

    Ambulatory arterial stiffness index (AASI) has been proposed as a new measure of arterial stiffness for predicting cardio-cerebro-vascular morbidity and mortality. However, there has been no research on the direct relationships between AASI and arterial stiffness-determining factors. We utilized beat-to-beat intra-aortic blood pressure (BP) telemetry to characterize AASI in Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). By determination of aortic structural components and analysis of their correlations with AASI, we provided the first direct evidence for the associations between AASI and arterial stiffness-determining factors including the collagen content and collagen/elastin. Ambulatory arterial stiffness index was positively correlated with pulse pressure in both WKY and SHR, less dependent on BP and BP variability than pulse pressure, and relatively stable, especially the number of BP readings not less than ~36. The correlations between AASI and aortic components were comparable for various AASI values derived from BP readings not less than ~36. Not only AASI but also BP variability and pulse pressure demonstrated a direct relationship with arterial stiffness. These findings indicate AASI may become a routine measure in human arterial stiffness assessment. It is recommended to use a cluster of parameters such as AASI, BP variability, and pulse pressure for evaluating arterial stiffness. © 2013 John Wiley & Sons Ltd.

  11. Roles of Rho-Associated Kinase and Oxidative Stress in the Pathogenesis of Aortic Stiffness

    Science.gov (United States)

    Noma, Kensuke; Goto, Chikara; Nishioka, Kenji; Jitsuiki, Daisuke; Umemura, Takashi; Ueda, Keiko; Kimura, Masashi; Nakagawa, Keigo; Oshima, Tetsuya; Chayama, Kazuaki; Yoshizumi, Masao; Liao, James K.; Higashi, Yukihito

    2008-01-01

    Objectives The purpose of this study was to determine the relationship between Rho-associated kinase (ROCK) activity and aortic stiffness in humans. Background Epidemiologic studies have shown that there is a relationship between aortic stiffness and cardiovascular complications. Recent evidence suggests that ROCK plays an important role in the process of atherosclerosis. Methods We evaluated the forearm blood flow (FBF) response to sodium nitroprusside (SNP), a nitric oxide donor, acetylcholine (ACh), an endothelium-dependent vasodilator, and fasudil, a specific ROCK inhibitor, in 51 healthy male subjects (mean age 45.6 ± 3.0 years). The FBF was measured by using a strain-gauge plethysmograph. Carotidfemoral pulse wave velocity (cf-PWV) was measured to assess the aortic stiffness using a pulse wave velocimeter. Results Intra-arterial infusion of SNP alone, ACh alone, or fasudil alone and after coinfusion of NG-monomethyl-L-arginine (L-NMMA), a nitric-oxide synthase inhibitor, significantly increased FBF in a dose-dependent manner (p < 0.01). Multivariate analysis showed that age and number of pack-years smoked were independent predictors of ROCK activity before or after co-infusion of L-NMMA (p < 0.01) and that age and ROCK activity before or after co-infusion of L-NMMA were independent predictors of cf-PWV (p < 0.01). The concentration of serum malondialdehyde-modified low-density lipoprotein, an index of oxidative stress, was significantly correlated with ROCK activity before and after co-infusion of L-NMMA and cf-PWV (p < 0.01). Conclusions These findings suggest that aging and accumulating smoking habit, which might induce excessive oxidative stress, are involved in ROCK activity in the vasculature, leading to an increase in aortic stiffness in humans. PMID:17291936

  12. Association of AHSG gene polymorphisms and aortic stiffness in peritoneal dialysis patients.

    Science.gov (United States)

    Jung, Ji Yong; Hwang, Young-Hwan; Lee, Hajeong; Ro, Han; Lee, Hankyu; Chung, Wookyung; Chae, Dong-Wan; Joo, Kwon Wook; Ahn, Curie; Oh, Kook-Hwan

    2010-01-01

    Fetuin-A is a negative acute-phase reactant and extraosseous calcification inhibitor. Decreased serum concentration of fetuin-A is independently related to all-cause and cardiovascular mortality in dialysis patients. Our aim is to investigate the association between the genetic polymorphism of alpha(2)-Heremans-Schmid-glycoprotein (AHSG) encoding fetuin-A and its serum concentration, vascular calcification, and aortic stiffness in peritoneal dialysis (PD) patients. A total of six single nucleotide polymorphisms (SNPs) in the AHSG gene were genotyped and evaluated for association with serum fetuin-A level, quantitative measures of vascular calcification and aortic stiffness represented by heart-to-femoral pulse wave velocity (hfPWV). Five SNPs in the AHSG gene were nominally associated with the serum fetuin-A level in our PD patients. In haplotype analyses, there were haplotypes positively (H1; AGCA, H2; CC) and inversely (H1; TTCG, H2; TT) related with the serum fetuin-A level. The serum fetuin-A level inversely and independently correlated with hfPWV. Moreover, the serum fetuin-A concentration was a determinant for the simple vascular calcification score (SVCS), which subsequently was associated with hfPWV. Our study showed an association between AHSG polymorphism and its serum concentration, and also revealed an association of the serum fetuin-A level with SVCS and aortic stiffness in PD patients. 2010 S. Karger AG, Basel.

  13. Aortic Stiffness, Ambulatory Blood Pressure, and Predictors of Response to Antihypertensive Therapy in Hemodialysis.

    Science.gov (United States)

    Georgianos, Panagiotis I; Agarwal, Rajiv

    2015-08-01

    Arterial stiffness is associated with elevated blood pressure (BP), but it is unclear whether it also makes hypertension more resistant to treatment. Among hypertensive dialysis patients, this study investigated whether aortic stiffness determines ambulatory BP and predicts its improvement with therapy. Post hoc analysis of the Hypertension in Hemodialysis Patients Treated With Atenolol or Lisinopril (HDPAL) trial. 179 hypertensive hemodialysis patients with echocardiographic left ventricular hypertrophy. Baseline aortic pulse wave velocity (PWV). Baseline and treatment-induced change in 44-hour ambulatory BP at 3, 6, and 12 months. Aortic PWV was assessed with an echocardiographic-Doppler technique (ACUSON Cypress, Siemens Medical), and 44-hour interdialytic ambulatory BP monitoring was performed with a Spacelabs 90207 monitor. Mean baseline aortic PWV was 7.6±2.7 (SD) m/s. Overall treatment-induced changes in ambulatory systolic BP (SBP) were -15.6±20.4, -18.9±22.5, and -20.0±19.7 mmHg at 3, 6, and 12 months. Changes in SBP were no different among tertiles of baseline PWV. Aortic PWV was associated directly with baseline ambulatory SBP and pulse pressure (PP) and inversely with diastolic BP (DBP). After adjustment for several cardiovascular risk factors, each 1-m/s higher PWV was associated with 1.34-mm Hg higher baseline SBP (β=1.34±0.46; P=0.004) and 1.02-mm Hg higher PP (β=1.02±0.33; P=0.002), whereas the association with DBP was no longer significant. Baseline PWV did not predict treatment-induced changes in SBP (Wald test, P=0.3) and DBP (Wald test, P=0.7), but was a predictor of an overall improvement in PP during follow-up (Wald test, P=0.03). Observational design; predominantly black patients were studied. Because aortic PWV is not a predictor of treatment-induced change in ambulatory BP among hypertensive dialysis patients, it indicates that among these patients, hypertension can be controlled successfully regardless of aortic stiffness

  14. Successful renal transplantation decreases aortic stiffness and increases vascular reactivity in dialysis patients.

    Science.gov (United States)

    Covic, A; Goldsmith, D J A; Gusbeth-Tatomir, P; Buhaescu, I; Covic, M

    2003-12-15

    Patients with end-stage renal disease on dialysis have among the highest cardiovascular event rates documented. Abnormal nitric oxide (NO)-dependent endothelial reactivity and increased arterial stiffness are commonly described in hemodialysis (HD) patients. Measures of aortic stiffness--aortic pulse wave velocity (PWV) and augmentation index (AGI)--have been shown to be powerful predictors of survival on hemodialysis. It is not known how these parameters interfere with successful renal transplantation. PWV and aortic AGI (difference between the first and second systolic peak on the aortic pressure waveform divided by the pulse wave height) were determined from contour analysis of arterial waveforms recorded by applanation tonometry using a SphygmoCor device in 41 HD patients (20 men; age, 41.8 years) and in a control group of 20 patients with essential hypertension (HTA) (10 men; age, 43.6 years). Twenty of the HD patients (10 men; age, 39.7 years) received live-related renal transplants (RTx) and were restudied (3 months after RTx, normal serum creatinine). NO-dependent and NO-independent vascular reactivity were assessed by changes in AGI after challenges with inhaled salbutamol (SAL) and sublingual nitroglycerin (NTG), respectively. AGI values were significantly lower in RTx patients compared with subjects on hemodialysis (15.9 +/- 13.9% vs. 27.9 +/- 11.9%, Pdialysis to 15.9 +/- 7.0% 3 months after transplantation (Pdialysis patients (7.19 +/- 1.88 m/sec) were significantly higher than those measured in essential HTA patients (6.34 +/- 1.32 m/sec, Pdialysis) values (P<0.05 for comparison) but similar to the control group of essential HTA patients. Renal transplantation is associated with marked improvements in vascular structure and function to a profile comparable to essential HTA patients.

  15. Elastic properties of the aorta and factors affecting aortic stiffness in patients with

    Directory of Open Access Journals (Sweden)

    Derya Tok

    2012-09-01

    Full Text Available Objectives: In this study, we evaluated aortic stiffnessand echocardiographic and laboratory factors affectingaortic stiffness in patients with metabolic syndrome(MetS.Materials and methods: Forty-six patients (25 male,mean age 47.3±6.5 years with the diagnosis of MetS accordingto the Adult Treatment Panel III Final Report criteriawere included. Forty-four age and gender matchedhealthy subjects (18 male, mean age 46.0±6.1 yearswere recruited as the control group. Aortic strain, distensibilityand stiffness index were calculated by M-modeechocardiography and diastolic parameters were measured.Results: Left ventricular mass index (LVMI, decelerationtime (DT, isovolumic relaxation time (IVRT wereincreased and mitral E/A ratio was decreased in patientswith MetS compared to controls. In the MetS patients,aortic distensibility was significantly decreased (10.4±3.5cm2.dyn-1.10-6 vs. 12.7±3.4 cm2.dyn-1.10-6, p=0.002,and ASI was significantly increased (6.5±2.0 vs. 3.2±0.8,p<0.001. ASI was positively correlated with triglycerides,fasting glucose, uric acid, hsCRP, LVMI, DT, IVRT andsystolic blood pressure level, and was negatively correlatedwith HDL-cholesterol and mitral E/A ratio. In regressionanalysis, hsCRP (p=0.05 and systolic blood pressurelevel (p<0.001 were independent predictors of ASI.Conclusions: ASI is increased in patients with MetS. Inthese patients; decrease in aortic elasticity properties wasassociated with left ventricular diastolic dysfunction. Highsystolic pressure and hsCRP levels were found to be independentpredictors of ASI.Key words: Metabolic syndrome, Echocardiography,elastic properties of aorta, hsCRP

  16. Socioeconomic status, education, and aortic stiffness progression over 5 years: the Whitehall II prospective cohort study.

    Science.gov (United States)

    Trudel, Xavier; Shipley, Martin J; McEniery, Carmel M; Wilkinson, Ian B; Brunner, Eric J

    2016-10-01

    The inverse association between socioeconomic status (SES) and cardiovascular disease (CVD) risk is well documented. Aortic stiffness assessed by aortic pulse wave velocity (PWV) is a strong predictor of CVD events. However, no previous study has examined the effect of SES on arterial stiffening over time. The present study examines this association, using several measures of SES, and attained education level in a large ageing cohort of British men and women. Participants were drawn from the Whitehall II study. The sample was composed of 3836 men and 1406 women who attended the 2008-2009 clinical examination (mean age = 65.5 years). Aortic PWV was measured in 2008-2009 and in 2012-2013 by applanation tonometry. A total of 3484 participants provided PWV measurements on both occasions. The mean difference in 5-year PWV change was examined according to household income, education, employment grade, and father's social class, using linear mixed models. PWV increase [mean: confidence interval (m/s)] over 5 years was higher among participants with lower employment grade (0.38: 0.11-0.65), household income (0.58, 95%: 0.32-0.85), and education (0.30: 0.01, 0.58), after adjusting for sociodemographic variables, BMI, alcohol consumption, smoking, and other cardiovascular risk factors, namely SBP, mean arterial pressure, heart rate, cholesterol, diabetes, and antihypertensive use. The present study supports the presence of robust socioeconomic disparities in aortic stiffness progression. Our findings suggest that arterial aging could be an important pathophysiological pathway explaining the impact of lower SES on CVD risk.

  17. Feasibility and accuracy of bedside transthoracic echocardiography in diagnosis of acute proximal aortic dissection.

    Science.gov (United States)

    Sobczyk, Dorota; Nycz, Krzysztof

    2015-03-25

    The purpose of the present study was to establish the accuracy of transthoracic echocardiography (TTE) in diagnosis of acute type A aortic dissection in comparison to computed tomography (CT), with reference to the intraoperative image. The retrospective analysis included 178 patients referred to the cardiac surgery unit in our center due to acute type A dissection between 01-01-2008 and 31-12-2013, who underwent both TTE and CT. Intraoperative image was considered as a reference. Statistical analysis did not show any significant differences between computed tomography and echocardiography in the detection of the proximal aortic dissection. In patients with aortic valve abnormalities, procedure of choice was replacement by a composite graft (77,59%), whereas patients with a normal image of aortic valve were more likely to have the valve sparing procedure (50,88%). The R-Spearman statistics shows a strong positive correlation between maximum diameter of ascending aorta measured by TTE and CT (cc 0.869) and TTE and intraoperative measurement (cc 0.844). Our data confirm that transthoracic echocardiography is a reliable method for diagnosis of proximal aortic dissection. TTE provides a reliable value of maximum diameter of the ascending aorta in comparison to both CT and direct intraoperative measurement. Moreover, transthoracic echocardiography gives the additional information that influences the operative technique of choice and identifies the high-risk patients (cardiac tamponade, severe aortic dilatation, severe aortic regurgitation). Our retrospective analysis confirms the pivotal role of TTE in the evaluation of the patients with suspected proximal aortic dissection in emergency room setting.

  18. Aortic inflammation, as assessed by hybrid FDG-PET/CT imaging, is associated with enhanced aortic stiffness in addition to concurrent calcification

    Energy Technology Data Exchange (ETDEWEB)

    Joly, Laure [CHU-Nancy, Department of Geriatric Medicine, Nancy (France); Nancy-University, Nancy (France); INSERM, U 684, Nancy (France); Djaballah, Wassila [INSERM, ERI 13, Nancy (France); CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Koehl, Gregory [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Mandry, Damien [Nancy-University, Nancy (France); INSERM, ERI 13, Nancy (France); CHU-Nancy, Department of Radiology, Nancy (France); Dolivet, Gilles [Centre Alexis Vautrin, Head and Neck Surgery Unit, Oncologic Surgery Department, Vandoeuvre-les-Nancy (France); Marie, Pierre-Yves [Nancy-University, Nancy (France); INSERM, U 684, Nancy (France); CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Benetos, Athanase [CHU-Nancy, Department of Geriatric Medicine, Nancy (France); Nancy-University, Nancy (France); INSERM, U 684, Nancy (France); CHU de Nancy, Centre de Geriatrie et Medecine Interne, Vandoeuvre les Nancy (France)

    2009-06-15

    To analyse the relationship between: (i) aortic pulse wave velocity (PWV), an index of aortic stiffness with strong prognostic significance, and (ii) aortic calcification and inflammation, which were quantified by hybrid imaging with X-ray computed tomography (CT) and {sup 18}F-fluorodeoxyglucose (FDG) positron emission tomography (PET). Central aortic (carotid-femoral) and peripheral (carotid-brachial and femoral-tibial) PWV were recorded in 26 patients, who had been routinely referred for dual FDG-PET/CT imaging. In univariate analyses, central aortic PWV was strongly linked to the volume of calcifications (VCa) and an enhanced FDG activity, when determined by averaging standardized uptake values (SUV{sub max}). By multivariate stepwise analysis including age and gender, both VCa (p < 0.0001) and SUV{sub max} (p < 0.01) were significant determinants of PWV explaining 61% and 11% of its variability. Aortic inflammation, assessed by hybrid FDG-PET/CT imaging, is associated with an enhanced aortic stiffness, in addition to the concurrent impact of calcifications. (orig.)

  19. Performance comparison of ultrasound-based methods to assess aortic diameter and stiffness in normal and aneurysmal mice.

    Directory of Open Access Journals (Sweden)

    Bram Trachet

    Full Text Available Several ultrasound-based methods are currently used to assess aortic diameter, circumferential strain and stiffness in mice, but none of them is flawless and a gold standard is lacking. We aimed to assess the validity and sensitivity of these methods in control animals and animals developing dissecting abdominal aortic aneurysm.We first compared systolic and diastolic diameters as well as local circumferential strains obtained in 47 Angiotensin II-infused ApoE(-/- mice with three different techniques (BMode, short axis MMode, long axis MMode, at two different abdominal aortic locations (supraceliac and paravisceral, and at three different time points of abdominal aneurysm formation (baseline, 14 days and 28 days. We found that short axis BMode was preferred to assess diameters, but should be avoided for strains. Short axis MMode gave good results for diameters but high standard deviations for strains. Long axis MMode should be avoided for diameters, and was comparable to short axis MMode for strains. We then compared pulse wave velocity measurements using global, ultrasound-based transit time or regional, pressure-based transit time in 10 control and 20 angiotensin II-infused, anti-TGF-Beta injected C57BL/6 mice. Both transit-time methods poorly correlated and were not able to detect a significant difference in PWV between controls and aneurysms. However, a combination of invasive pressure and MMode diameter, based on radio-frequency data, detected a highly significant difference in local aortic stiffness between controls and aneurysms, with low standard deviation.In small animal ultrasound the short axis view is preferred over the long axis view to measure aortic diameters, local methods are preferred over transit-time methods to measure aortic stiffness, invasive pressure-diameter data are preferred over non-invasive strains to measure local aortic stiffness, and the use of radiofrequency data improves the accuracy of diameter, strain as well

  20. Blunt traumatic aortic rupture of the proximal ascending aorta repaired by resection and direct anastomosis.

    Science.gov (United States)

    Harmouche, Majid; Slimani, Eric Karim; Heraudeau, Adeline; Verhoye, Jean-Philippe

    2013-10-01

    Traumatic aortic injury represents 15% of motor vehicle related deaths with death occurring at the scene in 85% of the cases. Aortic disruptions usually occur at the isthmus in a transverse fashion with all three of the aortic layers being involved. Herein, we report the case of a 68-year old man with no prior medical history who was struck by a vehicle while riding his bicycle. The ruptured segment of aorta was resected circumferentially and interrupted horizontal mattress pledgeted prolene sutures were used to ensure full thickness aortic integrity of the proximal and distal aortic segments. The aorta was closed with a single-layer technique using 4/0 prolene suture. There were no postoperative complications and patient was discharged on Day 44. The case here discussed demonstrates a rare presentation of blunt aortic injury. The proximal ascending aorta is an unusual site of transection following blunt trauma with few reports in the literature. We were able to repair the aorta with direct suture, thus avoiding the use of artificial material.

  1. Acute hypotension induced by aortic clamp vs. PTH provokes distinct proximal tubule Na+ transporter redistribution patterns

    DEFF Research Database (Denmark)

    Leong, Patrick K K; Yang, Li E; Lin, Harrison W

    2004-01-01

    in renal cortical membranes fractionated on sorbitol density gradients. Aortic clamp-induced acute hypotension (from 100 +/- 3 to 78 +/- 2 mmHg) provoked a 62% decrease in urine output and a significant decrease in volume flow from the proximal tubule detected as a 66% decrease in endogenous lithium......-density membranes enriched in apical markers. PTH at much lower doses (

  2. Mechanisms of improved aortic stiffness by arotinolol in spontaneously hypertensive rats.

    Directory of Open Access Journals (Sweden)

    Wugang Zhou

    Full Text Available OBJECTIVES: This study investigates the effects on aortic stiffness and vasodilation by arotinolol and the underlying mechanisms in spontaneously hypertensive rats (SHR. METHODS: The vasodilations of rat aortas, renal and mesenteric arteries were evaluated by isometric force recording. Nitric oxide (NO was measured in human aortic endothelial cells (HAECs by fluorescent probes. Sixteen-week old SHRs were treated with metoprolol (200 mg·kg-1·d⁻¹, arotinolol (30 mg·kg-1·d⁻¹ for 8 weeks. Central arterial pressure (CAP and pulse wave velocity (PWV were evaluated via catheter pressure transducers. Collagen was assessed by immunohistochemistry and biochemistry assay, while endothelial nitric oxide synthase (eNOS and eNOS phosphorylation (p-eNOS of HAECs or aortas were analyzed by western blotting. RESULTS: Arotinolol relaxed vascular rings and the relaxations were attenuated by Nω-nitro-L-arginine methyl ester (L-NAME, NO synthase inhibitor and the absence of endothelium. Furthermore, arotinolol-induced relaxations were attenuated by 4-aminopyridine (4-AP, Kv channels blocker. Arotinolol produced more nitric oxide compared to metoprolol and increased the expression of p-eNOS in HAECs. These results indicated that arotinolol-induced vasodilation involves endothelium-derived NO and Kv channels. The treatement with arotinolol in 8 weeks, but not metoprolol, markedly decreased CAP and PWV. Biochemistry assay and immunohistochemistry showed that aortic collagen depositions in the arotinolol groups were reduced compared with SHRs with metoprolol. Moreover, eNOS phosphorylation was significantly increased in aortinolol-treated SHR compared with SHRs with metoprolol. CONCLUSIONS: Arotinolol improves arterial stiffness in SHR, which involved in increasing NO and decreasing collagen contents in large arteries.

  3. Mechanisms of improved aortic stiffness by arotinolol in spontaneously hypertensive rats.

    Science.gov (United States)

    Zhou, Wugang; Hong, Mona; Zhang, Ke; Chen, Dongrui; Han, Weiqing; Shen, Weili; Zhu, Dingliang; Gao, Pingjin

    2014-01-01

    This study investigates the effects on aortic stiffness and vasodilation by arotinolol and the underlying mechanisms in spontaneously hypertensive rats (SHR). The vasodilations of rat aortas, renal and mesenteric arteries were evaluated by isometric force recording. Nitric oxide (NO) was measured in human aortic endothelial cells (HAECs) by fluorescent probes. Sixteen-week old SHRs were treated with metoprolol (200 mg·kg-1·d⁻¹), arotinolol (30 mg·kg-1·d⁻¹) for 8 weeks. Central arterial pressure (CAP) and pulse wave velocity (PWV) were evaluated via catheter pressure transducers. Collagen was assessed by immunohistochemistry and biochemistry assay, while endothelial nitric oxide synthase (eNOS) and eNOS phosphorylation (p-eNOS) of HAECs or aortas were analyzed by western blotting. Arotinolol relaxed vascular rings and the relaxations were attenuated by Nω-nitro-L-arginine methyl ester (L-NAME, NO synthase inhibitor) and the absence of endothelium. Furthermore, arotinolol-induced relaxations were attenuated by 4-aminopyridine (4-AP, Kv channels blocker). Arotinolol produced more nitric oxide compared to metoprolol and increased the expression of p-eNOS in HAECs. These results indicated that arotinolol-induced vasodilation involves endothelium-derived NO and Kv channels. The treatement with arotinolol in 8 weeks, but not metoprolol, markedly decreased CAP and PWV. Biochemistry assay and immunohistochemistry showed that aortic collagen depositions in the arotinolol groups were reduced compared with SHRs with metoprolol. Moreover, eNOS phosphorylation was significantly increased in aortinolol-treated SHR compared with SHRs with metoprolol. Arotinolol improves arterial stiffness in SHR, which involved in increasing NO and decreasing collagen contents in large arteries.

  4. Proximal endovascular blood flow shunt for thoracoabdominal aortic aneurism without total aortic clamping

    Directory of Open Access Journals (Sweden)

    Gaudencio Espinosa

    Full Text Available The authors present a surgical approach to type III and IV Crawford aneurysms that does not need total aortic clamping, which allows the more objective prevention of direct ischemic damage, as well as its exclusion by the endoprosthesis implantation, shunting the flow to the synthetic graft.

  5. Outcomes of a Less-Invasive Approach for Proximal Aortic Operations.

    Science.gov (United States)

    Levack, Melissa M; Aftab, Muhammad; Roselli, Eric E; Johnston, Douglas R; Soltesz, Edward G; Gillinov, A Marc; Pettersson, Gösta B; Griffin, Brian; Grimm, Richard; Hammer, Donald F; Al Kindi, Adil H; Albacker, Turki B; Sepulveda, Edgardo; Thuita, Lucy; Blackstone, Eugene H; Sabik, Joseph F; Svensson, Lars G

    2017-02-01

    Less-invasive techniques have previously been described for mitral and aortic valve operations; however, few studies have examined their benefit for aortic root and ascending aorta reconstruction. Using propensity matching, we compared outcomes of patients undergoing proximal aortic operations through a J incision compared with full sternotomy. From January 1995 to January 2014, 8,533 patients underwent proximal aortic operations at Cleveland Clinic. The study population comprised 1,827 patients after those with prior cardiac operations, emergency procedures, endocarditis, or circulatory arrest were excluded; 568 (31%) underwent a J incision. A propensity score based on 57 variables was generated to account for differences in characteristics of full-sternotomy and J-incision patients, producing 483 matched patient pairs (85% of possible) for comparison of outcomes. Among propensity-matched patients, in-hospital mortality (0 [0%] J incision vs 2 [0.41%] full sternotomy; p = 0.2), renal failure (3 [0.62%] vs 6 [1.2%]; p = 0.3), stroke (3 [0.62%] vs 3 [0.62%; p > 0.9), reoperation for bleeding (17 [3.5%] vs 15 [3.1%]; p = 0.7), intraoperative blood products (60 [15%] vs 78 [19%]; p = 0.08), and postoperative transfusions (97 [20%] vs 103 [22%]; p = 0.6) were similar. Intensive care unit (median 24 vs 26 hours) and postoperative hospital stays (median 5.2 vs 6.0 days) were shorter (p operative and postoperative direct technical costs were 6% less. A J incision is a feasible technique for primary isolated elective proximal aortic operations, with a low risk of complications similar to those of full sternotomy, but with the advantages of shorter intensive care unit and hospital stays, lower costs, and better cosmesis. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  6. Epicardial fat volume and aortic stiffness in healthy individuals. A quantitative cardiac magnetic resonance study

    Energy Technology Data Exchange (ETDEWEB)

    Homsi, R.; Thomas, D.; Meier-Schroers, M.; Dabir, D.; Kuetting, D.; Luetkens, J.A.; Marx, C.; Schild, H.H. [Bonn University Hospital (Germany). Radiology; Gieseke, J. [Philips Healthcare, Hamburg (Germany); Sprinkart, A. [Bonn University Hospital (Germany). Radiology; Bochum Univ. (Germany). Inst. of Medical Engineering

    2016-09-15

    To determine epicardial fat volume (EFV) and aortic stiffness (assessed by aortic pulse wave velocity (PWV)) in healthy individuals, and to investigate the relationship of these parameters, and their association with body mass index (BMI) and age. 58 subjects (29 men, mean age 44.7 ± 13.9 years[y]) underwent a CMR exam at 1.5 Tesla. A 2 D velocity-encoded CMR scan was acquired to determine PWV. The EFV was measured based on a 3 D-mDixon sequence. Group comparisons were made between younger (age < 45y; n=30; mean age 33.4 ± 6.6y) and older (> 45y; n=28; 56.7 ± 8.4y) subjects and between subjects with a BMI < 25 kg/m{sup 2} (n=28; BMI 21.9 ± 2.5 kg/m{sup 2}) and a BMI > 25 kg/m{sup 2} (n=30; 28.7 ± 4.0 kg/m{sup 2}). Associations between the determined parameters were assessed by analyses of covariance (ANCOVAs). The mean values of PWV and EFV (normalized to body surface area) were 6.9 ±1.9 m/s and 44.2 ± 25.0 ml/m{sup 2}, respectively. The PWV and EFV were significantly higher in the older group (PWV=7.9 ± 2.0 m/s vs. 6.0 ± 1.2 m/s; EFV=54.7 ml/m{sup 2} vs. 34.5 ml/m{sup 2}; p < 0.01, each), with no significant differences in BMI or sex. In the overweighted group the EFV was significantly higher than in subjects with a BMI < 25kg/m{sup 2} (EFV=56.1 ± 27.1 ml/m{sup 2} vs. 31.5 ± 14.6 ml/m{sup 2}; p < 0.01) but without a significant difference in PWV. ANCOVA revealed a significant correlation between EFV and PWV, also after adjustment for age (p=0.025). An association was found between age and EFV as well as PWV. EFV and PWV were related to each other also after adjustment for age. The metabolic and pro-inflammatory activity found with increased epicardial fat volume may promote the development of atherosclerosis and aortic stiffness. CMR may be valuable for future studies investigating the relationship between EFV and PWV in patients with increased cardiovascular risk.

  7. Effects of 6 months of abatacept treatment on aortic stiffness in patients with rheumatoid arthritis

    Directory of Open Access Journals (Sweden)

    Mathieu S

    2013-12-01

    Full Text Available Sylvain Mathieu,1,2 Marion Couderc,1,2 Baptiste Glace,1,2 Bruno Pereira,2,3 Anne Tournadre,1,2 Jean-Jacques Dubost,1,2 Martin Soubrier1,21Department of Rheumatology, Gabriel-Montpied Hospital, 2Faculty of Medicine, University Clermont 1, 3Délégation de la Recherche Clinique, Gabriel-Montpied Hospital, Clermont-Ferrand, FranceBackground: Systemic inflammation plays an important role in the increased cardiac risk observed in rheumatoid arthritis (RA. Effective control of inflammation and disease activity may be of benefit in reducing cardiovascular risk in RA patients.Objective: Our study was conducted in patients with active RA to investigate the effects of 24-week abatacept treatment on aortic stiffness measured by pulse wave velocity (PWV.Results: The study included 21 patients, of whom 17 were females, with a mean age of 65.2±13.7 years. Ten patients had positive rheumatoid factors, 16 positive anti-citrullinated protein antibodies, and 19 presented an erosive form of RA. Sixteen patients were nonresponders to anti-tumor necrosis factor-alpha treatments. After 6 months of abatacept treatment, there was a significant increase in PWV levels (9.8±2.9 versus 8.5±3.9 m/second; P=0.02. A nonsignificant increase in total cholesterol and low-density lipoprotein cholesterol was observed. There was also a significant increase in high-density lipoprotein cholesterol levels, which led to a nonsignificant decrease in atherogenic index. The improvement in disease activity was significant, and there was a decrease of systemic inflammatory parameters, but without reaching statistical significancy. Changes in PWV were significantly correlated with changes in Disease Activity Score on 28 joints based on erythrocyte sedimentation rate (r=0.46; P=0.035 and in high-density lipoprotein cholesterol (r=-0.38; P=0.046. No correlation was observed with changes in C-reactive protein and in other parameters of lipid profile or in steroid dose.Conclusion: The

  8. The combined effect of hypertension and type 2 diabetes mellitus on aortic stiffness and endothelial dysfunction: an integrated study with high-resolution MRI.

    Science.gov (United States)

    Shan, Yan; Lin, Jiang; Xu, Pengju; Zeng, Mengsu; Lin, Huandong; Yan, Hongmei

    2014-04-01

    The purpose of this study was to investigate the combined effect of hypertension and type 2 diabetes mellitus (DM2) on aortic stiffness and endothelial dysfunction by using an integrated MRI approach. A total of 31 non-hypertensive DM2 patients and 31 hypertensive DM2 patients underwent 3.0-T MRI. Aortic distensibility (AD), pulse wave velocity (PWV) and brachial artery flow-mediated dilation (FMD) were assessed. Student's t-test, Mann-Whitney U test, chi-squared test, Pearson correlation analysis, and univariable and multiple linear regression analyses were used for statistical analyses. The hypertensive patients showed lower AD at multiple levels (ascending aorta [AA]: 2.07±0.98×10(-3)mm Hg(-1) vs. 3.21±1.70×10(-3)mm Hg(-1), p<0.01; proximal thoracic descending aorta [PDA]: 2.58±0.72×10(-3)mm Hg(-1) vs. 3.58±1.47×10(-3)mm Hg(-1), p<0.01; distal descending aorta [DDA]: 3.11±1.84×10(-3)mm Hg(-1) vs. 4.27±1.75×10(-3)mm Hg(-1), p<0.01); faster PWV (7.46±2.28m/s vs. 5.82±1.12m/s, p<0.05) and lower FMD (12.67%±6.49% vs. 20.66%±9.7%; p<0.01). Systolic blood pressure was an independent predictor of PWV, AA-AD, DDA-AD and FMD. FMD was statistically significantly associated with PWV (r=-0.37, p<0.01) and AD (p<0.01). Hypertension has a contributive effect on aortic stiffness and endothelial dysfunction in DM2 patients. © 2013.

  9. Subendocardial viability ratio estimated by arterial tonometry: a critical evaluation in elderly hypertensive patients with increased aortic stiffness.

    Science.gov (United States)

    Chemla, Denis; Nitenberg, Alain; Teboul, Jean-Louis; Richard, Christian; Monnet, Xavier; le Clesiau, Hervé; Valensi, Paul; Brahimi, Mabrouk

    2008-08-01

    1. Increased aortic stiffness predisposes to myocardial ischaemia by increasing the systolic tension-time index and by decreasing aortic pressure throughout diastole. The tonometric subendocardial viability ratio (SEVR) is a non-invasive estimate of myocardial perfusion relative to cardiac workload. The hypothesis that SEVR is impaired in elderly hypertensives with high aortic pulse pressure (PP) was tested in the present study. 2. The SEVR was calculated by radial applanation tonometry in 203 subjects. In addition, diastolic time (DT), systolic time (ST) and mean diastolic and systolic aortic pressures (Pd and Ps, respectively) were calculated. First, 60 subjects matched for age and gender were analysed (20 controls, 20 hypertensives with pulse pressure (PP) 60 mmHg; mean (+/-SD) age 64 +/- 9 years; 24 women, 36 men). The remaining 143 subjects, aged 53 +/- 10 years, were analysed subsequently. 3. The SEVR was similar in the three elderly groups (1.39 +/- 0.34, 1.39 +/- 0.28 and 1.35 +/- 0.25, in controls and hypertensive patients with PP 60 mmHg, respectively). The SEVR was positively related to DT/ST (r(2) = 0.89) and to DT (r(2) = 0.73) and was negatively related to heart rate (r(2) = 0.56; P 60 mmHg than in hypertensives with normal PP. The positive linear relationship between SEVR and DT/ST was confirmed in the remaining 143 subjects (r(2) = 0.90), with no influence of aortic pressure. 4. The tonometric SEVR was not impaired in elderly hypertensive patients with increased aortic stiffness. In resting elderly and middle-aged individuals, the tonometric SEVR was mainly related to DT/ST ratio, not to aortic pressure.

  10. Preeclampsia Is Associated with Increased Central Aortic Pressure, Elastic Arteries Stiffness and Wave Reflections, and Resting and Recruitable Endothelial Dysfunction

    Directory of Open Access Journals (Sweden)

    Juan Torrado

    2015-01-01

    Full Text Available Introduction. An altered endothelial function (EF could be associated with preeclampsia (PE. However, more specific and complementary analyses are required to confirm this topic. Flow-mediated dilation (FMD, low-flow-mediated constriction (L-FMC, and hyperemic-related changes in carotid-radial pulse wave velocity (PWVcr offer complementary information about “recruitability” of EF. Objectives. To evaluate, in healthy and hypertensive pregnant women (with and without PE, central arterial parameters in conjunction with “basal and recruitable” EF. Methods. Nonhypertensive (HP and hypertensive pregnant women (gestational hypertension, GH; preeclampsia, PE were included. Aortic blood pressure (BP, wave reflection parameters (AIx@75, aortic pulse wave velocity (PWVcf and PWVcr, and brachial and common carotid stiffness and intima-media thickness were measured. Brachial FMD and L-FMC and hyperemic-related change in PWVcr were measured. Results. Aortic BP and AIx@75 were elevated in PE. PE showed stiffer elastic but not muscular arteries. After cuff deflation, PWVcr decreased in HP, while GH showed a blunted PWVcr response and PE showed a tendency to increase. Maximal FMD and L-FMC were observed in HP followed by GH; PE did not reach significant arterial constriction. Conclusion. Aortic BP and wave reflections as well as elastic arteries stiffness are increased in PE. PE showed both “resting and recruitable” endothelial dysfunctions.

  11. Receptor-based differences in human aortic smooth muscle cell membrane stiffness

    Science.gov (United States)

    Huang, H.; Kamm, R. D.; So, P. T.; Lee, R. T.

    2001-01-01

    Cells respond to mechanical stimuli with diverse molecular responses. The nature of the sensory mechanism involved in mechanotransduction is not known, but integrins may play an important role. The integrins are linked to both the cytoskeleton and extracellular matrix, suggesting that probing cells via integrins should yield different mechanical properties than probing cells via non-cytoskeleton-associated receptors. To test the hypothesis that the mechanical properties of a cell are dependent on the receptor on which the stress is applied, human aortic smooth muscle cells were plated, and magnetic beads, targeted either to the integrins via fibronectin or to the transferrin receptor by use of an IgG antibody, were attached to the cell surface. The resistance of the cell to deformation ("stiffness") was estimated by oscillating the magnetic beads at 1 Hz by use of single-pole magnetic tweezers at 2 different magnitudes. The ratio of bead displacements at different magnitudes was used to explore the mechanical properties of the cells. Cells stressed via the integrins required approximately 10-fold more force to obtain the same bead displacements as the cells stressed via the transferrin receptors. Cells stressed via integrins showed stiffening behavior as the force was increased, whereas this stiffening was significantly less for cells stressed via the transferrin receptor (Pcells depend on the receptor by which the stress is applied, with integrin-based linkages demonstrating cell-stiffening behavior.

  12. Receptor-based differences in human aortic smooth muscle cell membrane stiffness

    Science.gov (United States)

    Huang, H.; Kamm, R. D.; So, P. T.; Lee, R. T.

    2001-01-01

    Cells respond to mechanical stimuli with diverse molecular responses. The nature of the sensory mechanism involved in mechanotransduction is not known, but integrins may play an important role. The integrins are linked to both the cytoskeleton and extracellular matrix, suggesting that probing cells via integrins should yield different mechanical properties than probing cells via non-cytoskeleton-associated receptors. To test the hypothesis that the mechanical properties of a cell are dependent on the receptor on which the stress is applied, human aortic smooth muscle cells were plated, and magnetic beads, targeted either to the integrins via fibronectin or to the transferrin receptor by use of an IgG antibody, were attached to the cell surface. The resistance of the cell to deformation ("stiffness") was estimated by oscillating the magnetic beads at 1 Hz by use of single-pole magnetic tweezers at 2 different magnitudes. The ratio of bead displacements at different magnitudes was used to explore the mechanical properties of the cells. Cells stressed via the integrins required approximately 10-fold more force to obtain the same bead displacements as the cells stressed via the transferrin receptors. Cells stressed via integrins showed stiffening behavior as the force was increased, whereas this stiffening was significantly less for cells stressed via the transferrin receptor (Pmuscle cells depend on the receptor by which the stress is applied, with integrin-based linkages demonstrating cell-stiffening behavior.

  13. Aortic stiffness is related to left ventricular diastolic function in patients with diabetes mellitus type 1: assessment with MRI and speckle tracking strain analysis

    NARCIS (Netherlands)

    Schinkel, L.D. van; Auger, D.; Elderen, S.G. van; Ajmone Marsan, N.; Delgado, V.; Lamb, H.J.; Ng, A.C.; Smit, J.W.A.; Bax, J.J.; Westenberg, J.J.; Roos, A. de

    2013-01-01

    Diabetes mellitus type 1 (DM1) is associated with aortic stiffening and left ventricular (LV) diastolic dysfunction, however the relationship between aortic stiffness and LV diastolic dysfunction in DM1 patients is still largely unknown. The purpose of this study was to evaluate whether an increased

  14. Aortic stiffness is associated with cardiac function and cerebral small vessel disease in patients with type 1 diabetes mellitus: assessment by magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Elderen, Saskia G.C. van; Brandts, A.; Westenberg, J.J.M.; Grond, J. van der; Buchem, M.A. van; Kroft, L.J.M.; Roos, A. de [Leiden University Medical Center, Department of Radiology, Leiden (Netherlands); Tamsma, J.T.; Romijn, J.A.; Smit, J.W.A. [Leiden University Medical Center, Department of Endocrinology, Leiden (Netherlands)

    2010-05-15

    To evaluate, with the use of magnetic resonance imaging (MRI), whether aortic pulse wave velocity (PWV) is associated with cardiac left ventricular (LV) function and mass as well as with cerebral small vessel disease in patients with type 1 diabetes mellitus (DM). We included 86 consecutive type 1 DM patients (49 male, mean age 46.9 {+-} 11.7 years) in a prospective, cross-sectional study. Exclusion criteria included aortic/heart disease and general MRI contra-indications. MRI of the aorta, heart and brain was performed for assessment of aortic PWV, as a marker of aortic stiffness, systolic LV function and mass, as well as for the presence of cerebral white matter hyperintensities (WMHs), microbleeds and lacunar infarcts. Multivariate linear or logistic regression was performed to analyse the association between aortic PWV and outcome parameters, with covariates defined as age, gender, mean arterial pressure, heart rate, BMI, smoking, DM duration and hypertension. Mean aortic PWV was 7.1 {+-} 2.5 m/s. Aortic PWV was independently associated with LV ejection fraction (ss= -0.406, P = 0.006), LV stroke volume (ss=-0.407, P = 0.001), LV cardiac output (ss= -0.458, P = 0.001), and with cerebral WMHs (P < 0.05). There were no independent associations between aortic stiffness and LV mass, cerebral microbleeds or lacunar infarcts. Aortic stiffness is independently associated with systolic LV function and cerebral WMHs in patients with type 1 DM. (orig.)

  15. Techniques of Proximal Root Reconstruction and Outcomes Following Repair of Acute Type A Aortic Dissection.

    Science.gov (United States)

    Gunn, Tyler M; Stamou, Sotiris C; Kouchoukos, Nicholas T; Lobdell, Kevin W; Khabbaz, Kamal; Patzelt, Lawrence H; Hagberg, Robert C

    2016-04-01

    The goal of this study was to compare the early and late outcomes of different techniques of proximal root reconstruction during the repair of acute Type A aortic dissection, including aortic valve (AV) resuspension, aortic valve replacement (AVR), and a root replacement procedure. All patients who underwent acute Type A aortic dissection repair between January 2000 and October 2010 at four academic institutions were compiled from each institution's Society of Thoracic Surgeons Database. This included 189 patients who underwent a concomitant aortic valve (AV) procedure; 111, 21, and 57 patients underwent AV resuspension, AVR, and the Bentall procedure, respectively. The median age of patients undergoing a root replacement procedure was significantly younger than the other two groups. Early clinical outcomes and 10-year actuarial survival rates were compared. Trends in outcomes and surgical techniques throughout the duration of the study were also analyzed. The operative mortality rates were 17%, 29%, and 18%, for AV resuspension, AVR, and root replacement, respectively. Operative mortality (p = 0.459) was comparable between groups. Hemorrhage related re-exploration did not differ significantly between groups (p = 0.182); however, root replacement procedures tended to have decreased rates of bleeding when compared to AVR (p = 0.067). The 10-year actuarial survival rates for the AV resuspension, Bentall, and AVR groups were 72%, 56%, and 36%, respectively (log-rank p = 0.035). The 10-year actuarial survival was significantly lower in those receiving AVR compared to those receiving root replacement procedures or AV resuspension. Operative mortality was comparable between the three groups.

  16. Association of Aortic Stiffness With Cognition and Brain Aging in Young and Middle-Aged Adults: The Framingham Third Generation Cohort Study.

    Science.gov (United States)

    Pase, Matthew P; Himali, Jayandra J; Mitchell, Gary F; Beiser, Alexa; Maillard, Pauline; Tsao, Connie; Larson, Martin G; DeCarli, Charles; Vasan, Ramachandran S; Seshadri, Sudha

    2016-03-01

    Aortic stiffness is associated with cognitive decline and cerebrovascular disease late in life, although these associations have not been examined in young adults. Understanding the effects of aortic stiffness on the brain at a young age is important both from a pathophysiological and public health perspective. The aim of this study was to examine the cross-sectional associations of aortic stiffness with cognitive function and brain aging in the Framingham Heart Study Third Generation cohort (47% men; mean age, 46 years). Participants completed the assessment of aortic stiffness (carotid-femoral pulse wave velocity), a neuropsychological test battery assessing multiple domains of cognitive performance and magnetic resonance imaging to examine subclinical markers of brain injury. In adjusted regression models, higher aortic stiffness was associated with poorer processing speed and executive function (Trail Making B-A; β±SE, -0.08±0.03; Pbrain injury in young to middle-aged adults. Prospective studies are needed to examine whether aortic stiffening in young adulthood is associated with vascular cognitive impairment later in life. © 2016 American Heart Association, Inc.

  17. The relationship between aortic stiffness and cardiac function in patients with obstructive sleep apnea, independently from systemic hypertension.

    Science.gov (United States)

    Tavil, Yusuf; Kanbay, Asiye; Sen, Nihat; Ulukavak Ciftçi, Tansu; Abaci, Adnan; Yalçin, M Ridvan; Köktürk, Oğuz; Cengel, Atiye

    2007-04-01

    We sought to evaluate aortic function and its relationship with left ventricular (LV) function in patients with obstructive sleep apnea syndrome (OSAS), with or without systemic hypertension. A total of 29 patients with OSAS, 28 patients with systemic hypertension without OSAS, and 19 patients having both disorders were chosen as a study group, and 29 participants without these two disorders were taken as the control group; none of the patients had a history of cardiac disease. All of them underwent echocardiography and polysomnography. Aortic strain and distensibility were calculated from the aortic diameters measured by echocardiography and blood pressure obtained by cuff-sphygmomanometer. Cardiac functions were determined using echocardiography comprising standard 2-dimensional and conventional Doppler and Doppler tissue imaging. Aortic strain (mean +/- SD; 6.1 +/- 2.7% vs 6.4 +/- 2.4%, 4.7 +/- 1.8%, and 13.7 +/- 4.5%, P < .001, respectively) and distensibility (mean +/- SD 2.8 +/- 1.6 vs 2.5 +/- 0.9, 1.7 +/- 0.7, and 6.2 +/- 3.2 10(-6) cm(2) dyn(-1)P < .001, respectively) were significantly decreased in the patient groups (OSAS, hypertensive, and OSAS and hypertensive) compared with the control group. LV long-axis and diastolic functions were also impaired in the study group. There were good correlations between the aortic stiffness and LV function parameters. In a multivariate analysis, aortic strain was the parameter found to be most strongly associated both with the Doppler tissue imaging mean peak early/late diastolic velocity ratio and the LV mitral lateral annular plane systolic excursion. Aortic stiffness parameters (aortic strain and distensibility), LV systolic long-axis function indicators (mitral lateral annular plane systolic excursion, peak systolic myocardial velocity at lateral annulus, peak systolic myocardial velocity at septal annulus), and Doppler tissue imaging-derived LV diastolic indices were found abnormal in patients with OSAS

  18. Uncertainty quantification of inflow boundary condition and proximal arterial stiffness-coupled effect on pulse wave propagation in a vascular network.

    Science.gov (United States)

    Brault, Antoine; Dumas, Laurent; Lucor, Didier

    2017-10-01

    This work aims at quantifying the effect of inherent uncertainties from cardiac output on the sensitivity of a human compliant arterial network response based on stochastic simulations of a reduced-order pulse wave propagation model. A simple pulsatile output form is used to reproduce the most relevant cardiac features with a minimum number of parameters associated with left ventricle dynamics. Another source of significant uncertainty is the spatial heterogeneity of the aortic compliance, which plays a key role in the propagation and damping of pulse waves generated at each cardiac cycle. A continuous representation of the aortic stiffness in the form of a generic random field of prescribed spatial correlation is then considered. Making use of a stochastic sparse pseudospectral method, we investigate the sensitivity of the pulse pressure and waves reflection magnitude over the arterial tree with respect to the different model uncertainties. Results indicate that uncertainties related to the shape and magnitude of the prescribed inlet flow in the proximal aorta can lead to potent variation of both the mean value and standard deviation of blood flow velocity and pressure dynamics due to the interaction of different wave propagation and reflection features. Lack of accurate knowledge in the stiffness properties of the aorta, resulting in uncertainty in the pulse wave velocity in that region, strongly modifies the statistical response, with a global increase in the variability of the quantities of interest and a spatial redistribution of the regions of higher sensitivity. These results will provide some guidance in clinical data acquisition and future coupling of arterial pulse wave propagation reduced-order model with more complex beating heart models. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Evaluation of Distensibility and Stiffness of Ascending Aortic Aneurysm using Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    Kaushal Kishore Tiwari

    2016-12-01

    Conclusions: MRI measurement of aortic diameters, distensibility, and flow wave velocity is an easy, reliable and reproducible technique. Distensibility and pulse wave velocity define the elasticity of the aorta. We have observed that elasticity of aortic wall is decreased in ascending aorta aneurysm patients. Keywords: ascending aorta aneurysm; distensibility; pulse wave velocity; MRI. | PubMed

  20. Effects of age-associated regional changes in aortic stiffness on human hemodynamics revealed by computational modeling.

    Directory of Open Access Journals (Sweden)

    Federica Cuomo

    Full Text Available Although considered by many as the gold standard clinical measure of arterial stiffness, carotid-to-femoral pulse wave velocity (cf-PWV averages material and geometric properties over a large portion of the central arterial tree. Given that such properties may evolve differentially as a function of region in cases of hypertension and aging, among other conditions, there is a need to evaluate the potential utility of cf-PWV as an early diagnostic of progressive vascular stiffening. In this paper, we introduce a data-driven fluid-solid-interaction computational model of the human aorta to simulate effects of aging-related changes in regional wall properties (e.g., biaxial material stiffness and wall thickness and conduit geometry (e.g., vessel caliber, length, and tortuosity on several metrics of arterial stiffness, including distensibility, augmented pulse pressure, and cyclic changes in stored elastic energy. Using the best available biomechanical data, our results for PWV compare well to findings reported for large population studies while rendering a higher resolution description of evolving local and global metrics of aortic stiffening. Our results reveal similar spatio-temporal trends between stiffness and its surrogate metrics, except PWV, thus indicating a complex dependency of the latter on geometry. Lastly, our analysis highlights the importance of the tethering exerted by external tissues, which was iteratively estimated until hemodynamic simulations recovered typical values of tissue properties, pulse pressure, and PWV for each age group.

  1. Regulation of proximal tubular cell differentiation and proliferation in primary culture by matrix stiffness and ECM components.

    Science.gov (United States)

    Chen, Wan-Chun; Lin, Hsi-Hui; Tang, Ming-Jer

    2014-09-15

    To explore whether matrix stiffness affects cell differentiation, proliferation, and transforming growth factor (TGF)-β1-induced epithelial-mesenchymal transition (EMT) in primary cultures of mouse proximal tubular epithelial cells (mPTECs), we used a soft matrix made from monomeric collagen type I-coated polyacrylamide gel or matrigel (MG). Both kinds of soft matrix benefited primary mPTECs to retain tubular-like morphology with differentiation and growth arrest and to evade TGF-β1-induced EMT. However, the potent effect of MG on mPTEC differentiation was suppressed by glutaraldehyde-induced cross-linking and subsequently stiffening MG or by an increasing ratio of collagen in the soft mixed gel. Culture media supplemented with MG also helped mPTECs to retain tubular-like morphology and a differentiated phenotype on stiff culture dishes as soft MG did. We further found that the protein level and activity of ERK were scaled with the matrix stiffness. U-0126, a MEK inhibitor, abolished the stiff matrix-induced dedifferentiation and proliferation. These data suggest that the ERK signaling pathway plays a vital role in matrix stiffness-regulated cell growth and differentiation. Taken together, both compliant property and specific MG signals from the matrix are required for the regulation of epithelial differentiation and proliferation. This study provides a basic understanding of how physical and chemical cues derived from the extracellular matrix regulate the physiological function of proximal tubules and the pathological development of renal fibrosis. Copyright © 2014 the American Physiological Society.

  2. Reduction in Torsional Stiffness and Strength at the Proximal Tibia as a Function of Time Since Spinal Cord Injury.

    Science.gov (United States)

    Edwards, W Brent; Simonian, Narina; Troy, Karen L; Schnitzer, Thomas J

    2015-08-01

    Spinal cord injury (SCI) is characterized by marked bone loss and a high rate of low-energy fracture around regions of the knee. Changes in the mechanical integrity of bone after SCI are poorly defined, and a better understanding may inform approaches to prevent fractures. The purpose of this study was to quantify reductions in torsional stiffness and strength at the proximal tibia as a function of time since SCI. Sixty adults with SCI ranging from 0 to 50 years of duration and a reference group of 10 able-bodied controls received a CT scan of the proximal tibia. Measures of integral bone mineral were calculated for the total proximal tibia, and localized measures of cortical and trabecular bone mineral were calculated for the epiphysis, metaphysis, and diaphysis. Torsional stiffness (K) and strength (T(ult)) for the total proximal tibia were quantified using validated subject-specific finite element models. Total proximal tibia measures of integral bone mineral, K, and T(ult) decreased exponentially (r(2)  = 0.52 to 0.70) and reached a new steady state within 2.1 to 2.7 years after SCI. Whereas new steady-state values for integral bone mineral and K were 52% to 56% (p tibia measures occurred through a combination of trabecular and endocortical resorption, leaving a bone comprised primarily of marrow fat rather than hydroxyapatite. These findings illustrate that a short therapeutic window exists early (ie, 2 years) after SCI, during which bone-specific intervention may attenuate reductions in mechanical integrity and ultimately prevent SCI-related fragility fracture. © 2015 American Society for Bone and Mineral Research.

  3. Bone mineral and stiffness loss at the distal femur and proximal tibia in acute spinal cord injury.

    Science.gov (United States)

    Edwards, W B; Schnitzer, T J; Troy, K L

    2014-03-01

    Computed tomography and finite element modeling were used to assess bone mineral and stiffness loss at the knee following acute spinal cord injury (SCI). Marked bone mineral loss was observed from a combination of trabecular and endocortical resorption. Reductions in stiffness were 2-fold greater than reductions in integral bone mineral. SCI is associated with a rapid loss of bone mineral and an increased rate of fragility fracture. The large majority of these fractures occur around regions of the knee. Our purpose was to quantify changes to bone mineral, geometry, strength indices, and stiffness at the distal femur and proximal tibia in acute SCI. Quantitative computed tomography (QCT) and patient-specific finite element analysis were performed on 13 subjects with acute SCI at serial time points separated by a mean of 3.5 months (range 2.6-4.8 months). Changes in bone mineral content (BMC) and volumetric bone mineral density (vBMD) were quantified for integral, trabecular, and cortical bone at epiphyseal, metaphyseal, and diaphyseal regions of the distal femur and proximal tibia. Changes in bone volumes, cross-sectional areas, strength indices and stiffness were also determined. Bone mineral loss was similar in magnitude at the distal femur and proximal tibia. Reductions were most pronounced at epiphyseal regions, ranging from 3.0 % to 3.6 % per month for integral BMC (p < 0.001) and from 2.8 % to 3.4 % per month (p < 0.001) for integral vBMC. Trabecular BMC decreased by 3.1-4.4 %/month (p < 0.001) and trabecular vBMD by 2.7-4.7 %/month (p < 0.001). A 3.8-5.4 %/month reduction was observed for cortical BMC (p < 0.001); the reduction in cortical vBMD was noticeably lower (0.6-0.8 %/month; p ≤ 0.01). The cortical bone loss occurred primarily through endosteal resorption, and reductions in strength indices and stiffness were some 2-fold greater than reductions in integral bone mineral. These findings highlight the need for therapeutic

  4. Is there alteration in aortic stiffness in Leber hereditary optic neuropathy?

    NARCIS (Netherlands)

    Nemes, A.; Coo, I.F.M. de; Spruijt, L.; Smeets, H.J.; Chinnery, P.F.; Soliman, O.I.; Geleijnse, M.L.; Cate, FJ Ten

    2008-01-01

    PURPOSE: Leber hereditary optic neuropathy (LHON) is recognized as the most common cause of isolated blindness in young men. The current study was designed to test whether LHON as a mitochondrial disease is associated with vascular functional alterations characterized by aortic elastic properties

  5. Increased blood pressure and aortic stiffness among abusers of anabolic androgenic steroids

    DEFF Research Database (Denmark)

    Rasmussen, Jon J; Schou, Morten; Madsen, Per L

    2018-01-01

    BACKGROUND: Abuse of anabolic androgenic steroids (AAS) is prevalent among recreational athletes and adverse effects on blood pressure (BP) and arterial stiffness could be substantial. Testosterone decreases natriuretic peptides which are key components in BP-regulation and may impair BP...

  6. A database of virtual healthy subjects to assess the accuracy of foot-to-foot pulse wave velocities for estimation of aortic stiffness.

    Science.gov (United States)

    Willemet, Marie; Chowienczyk, Phil; Alastruey, Jordi

    2015-08-15

    While central (carotid-femoral) foot-to-foot pulse wave velocity (PWV) is considered to be the gold standard for the estimation of aortic arterial stiffness, peripheral foot-to-foot PWV (brachial-ankle, femoral-ankle, and carotid-radial) are being studied as substitutes of this central measurement. We present a novel methodology to assess theoretically these computed indexes and the hemodynamics mechanisms relating them. We created a database of 3,325 virtual healthy adult subjects using a validated one-dimensional model of the arterial hemodynamics, with cardiac and arterial parameters varied within physiological healthy ranges. For each virtual subject, foot-to-foot PWV was computed from numerical pressure waveforms at the same locations where clinical measurements are commonly taken. Our numerical results confirm clinical observations: 1) carotid-femoral PWV is a good indicator of aortic stiffness and correlates well with aortic PWV; 2) brachial-ankle PWV overestimates aortic PWV and is related to the stiffness and geometry of both elastic and muscular arteries; and 3) muscular PWV (carotid-radial, femoral-ankle) does not capture the stiffening of the aorta and should therefore not be used as a surrogate for aortic stiffness. In addition, our analysis highlights that the foot-to-foot PWV algorithm is sensitive to the presence of reflected waves in late diastole, which introduce errors in the PWV estimates. In this study, we have created a database of virtual healthy subjects, which can be used to assess theoretically the efficiency of physiological indexes based on pulse wave analysis. Copyright © 2015 the American Physiological Society.

  7. Increased stiffness is the major early abnormality in a pig model of severe aortic stenosis and predisposes to congestive heart failure in the absence of systolic dysfunction.

    Science.gov (United States)

    Ishikawa, Kiyotake; Aguero, Jaume; Oh, Jae Gyun; Hammoudi, Nadjib; Fish, Lauren A; Leonardson, Lauren; Picatoste, Belén; Santos-Gallego, Carlos G; Fish, Kenneth M; Hajjar, Roger J

    2015-05-20

    It remains unclear whether abnormal systolic function and relaxation are essential for developing heart failure in pathophysiology of severe aortic stenosis. Yorkshire pigs underwent surgical banding of the ascending aorta. The animals were followed for up to 5 months after surgery, and cardiac function was assessed comprehensively by invasive pressure-volume measurements, 3-dimensional echocardiography, echocardiographic speckle-tracking strain, and postmortem molecular and histological analyses. Pigs with aortic banding (n=6) exhibited significant left ventricular hypertrophy with increased stiffness compared with the control pigs (n=7) (end-diastolic pressure-volume relationship β: 0.053±0.017 versus 0.028±0.009 mm Hg/mL, P=0.007); however, all other parameters corresponding to systolic function, including ejection fraction, end-systolic pressure-volume relationship, preload recruitable stroke work, echocardiographic circumferential strain, and longitudinal strain, were not impaired in pigs with aortic banding. Relaxation parameters were also similar between groups. Sarcoplasmic reticulum calcium (Ca(2+)) ATPase protein levels in the left ventricle were similar. There were significant increases in 3-dimensional echocardiographic left atrial volumes, suggesting the usefulness of these indexes to detect increased stiffness. Right atrial pacing with a heart rate of 120 beats per minute induced increased end-diastolic pressure in pigs with aortic banding in contrast to decreased end-diastolic pressure in the control pigs. Histological evaluation revealed that increased stiffness was accompanied by cardiomyocyte hypertrophy and increased perimysial and perivascular fibrosis. Increased stiffness is the major early pathological process that predisposes to congestive heart failure without abnormalities in systolic function and relaxation in a clinically relevant animal model of aortic stenosis. © 2015 The Authors. Published on behalf of the American Heart

  8. Stiffness and Adhesivity Control Aortic Valve Interstitial Cell Behavior within Hyaluronic Acid Based Hydrogels

    Science.gov (United States)

    Duan, Bin; Hockaday, Laura A.; Kapetanovic, Edi; Kang, Kevin H.; Butcher, Jonathan T.

    2013-01-01

    Bioactive and biodegradable hydrogels that mimic the extracellular matrix and regulate valve interstitial cells (VIC) behavior are of great interest as three dimensional (3D) model systems for understanding mechanisms of valvular heart disease pathogenesis in vitro and the basis for regenerative templates for tissue engineering. However, the role of stiffness and adhesivity of hydrogels in VIC behavior remains poorly understood. This study reports synthesis of oxidized and methacrylated hyaluronic acid (Me-HA and MOHA) and subsequent development of hybrid hydrogels based on modified HA and methacrylated gelatin (Me-Gel) for VIC encapsulation. The mechanical stiffness and swelling ratio of the hydrogels were tunable with molecular weight of HA and concentration/composition of precursor solution. The encapsulated VIC in pure HA hydrogels with lower mechanical stiffness showed more spreading morphology comparing to stiffer counterparts and dramatically upregulated alpha smooth muscle actin expression indicating more activated myofibroblast properties. The addition of Me-Gel in Me-HA facilitated cell spreading, proliferation and VIC migration from encapsulated spheroids and better maintained VIC fibroblastic phenotype. The VIC phenotype transition during migration from encapsulated spheroids in both Me-HA and Me-HA/Me-Gel hydrogel matrix was also observed. These findings are important for the rational design of hydrogels for controlling VIC morphology, and for regulating VIC phenotype and function. The Me-HA/Me-Gel hybrid hydrogels accommodated with VIC are promising as valve tissue engineering scaffolds and 3D model for understanding valvular pathobiology. PMID:23648571

  9. Numerical assessment and comparison of pulse wave velocity methods aiming at measuring aortic stiffness.

    Science.gov (United States)

    Obeid, Hasan; Soulat, Gilles; Mousseaux, Elie; Laurent, Stéphane; Stergiopulos, Nikos; Boutouyrie, Pierre; Segers, Patrick

    2017-10-31

    Pulse waveform analyses have become established components of cardiovascular research. Recently several methods have been proposed as tools to measure aortic pulse wave velocity (aPWV). The carotid-femoral pulse wave velocity (cf-PWV), the current clinical gold standard method for the noninvasive assessment of aPWV, uses the carotid-to-femoral pulse transit time difference (cf-PTT) and an estimated path length to derive cf-PWV. The heart-ankle PWV (ha-PWV), brachial-ankle PWV (ba-PWV) and finger-toe (ft-PWV) are also methods presuming to approximate aPWV based on time delays between physiological cardiovascular signals at two locations (~heart-ankle PTT, ha-PTT; ~brachial-ankle PTT, ba-PTT; ~finger-toe PTT, ft-PTT) and a path length typically derived from the subject's height. To test the validity of these methods, we used a detailed 1D arterial network model (143 arterial segments) including the foot and hand circulation. The arterial tree dimensions and properties were taken from the literature and completed with data from patient scans. We calculated PTTs with all the methods mentioned above. The calculated PTTs were compared with the aortic PTT (aPTT), which is considered as the absolute reference method in this study. The correlation between methods and aPTT was good and significant, cf-PTT (R 2  =  0.97; P  methods, but absolute values differed because of the different path lengths used. In conclusion, our computer model-based analyses demonstrate that for PWV methods based on peripheral signals, pulse transit time differences closely correlate with the aortic transit time, supporting the use of these methods in clinical practice.

  10. A Systematic Review of Proximal Neck Dilatation After Endovascular Repair for Abdominal Aortic Aneurysm.

    Science.gov (United States)

    Kouvelos, George N; Oikonomou, Kyriakos; Antoniou, George A; Verhoeven, Eric L G; Katsargyris, Athanasios

    2017-02-01

    To provide an updated systematic literature review and summarize current evidence on proximal aortic neck dilatation (AND) after endovascular aneurysm repair (EVAR). A review of the English-language medical literature from 1991 to 2015 was conducted using MEDLINE and EMBASE to identify studies reporting AND after EVAR. Studies considered for inclusion and full-text review fulfilled the following criteria: (1) reported AND after EVAR, (2) included at least 5 patients, and (3) provided data on AND quantification. The search identified 26 articles published between 1998 and 2015 that encompassed 9721 patients (median age 71.8 years; 9439 men). AND occurred in 24.6% of patients (95% CI 18.6% to 31.8%) over a period ranging from 15 months to 9 years after EVAR. No significant dilatation of the suprarenal part of the aorta was reported by most studies. The incidence of combined clinical events (endoleak type I, migration, reintervention during follow-up) was higher in the AND group (26%) when compared with 2% in the group without AND (OR 28.7, 95% CI 5.43 to 151.67, p<0.001). AND affects a considerable proportion of EVAR patients and was related to worse clinical outcome, as indicated by increased rates of type I endoleak, migration, and reinterventions. Future studies should focus on a better understanding of the pathophysiology, predictors, and risk factors of AND, which could identify patients who may warrant a different EVAR strategy and/or a closer post-EVAR surveillance strategy.

  11. Higher Physical Activity Is Associated With Lower Aortic Stiffness but Not With Central Blood Pressure

    DEFF Research Database (Denmark)

    Laursen, Anne Sofie Dam; Hansen, Anne-Louise Smidt; Wiinberg, Niels

    2015-01-01

    sedentary behavior with 1 hour light or moderate-to-vigorous physical activity on central hemodynamics was examined. Median physical activity energy expenditure was 28.0 kJ/kg/d (IQR: 19.8; 38.7). A 10 kJ/kg/d higher energy expenditure was associated with 0.75% lower aortic pulse wave velocity (CI: -1.......47; -0.03). Associations with central systolic blood pressure and central pulse pressure were not statistically significant. We observed no difference in central hemodynamics when substituting 1 hour sedentary behavior with 1 hour light or moderate-to-vigorous physical activity. In this relatively...

  12. Influence of plate material and screw design on stiffness and ultimate load of locked plating in osteoporotic proximal humeral fractures.

    Science.gov (United States)

    Katthagen, Jan Christoph; Schwarze, Michael; Warnhoff, Mara; Voigt, Christine; Hurschler, Christof; Lill, Helmut

    2016-03-01

    The main purpose was to compare the biomechanical properties of a carbon-fibre reinforced polyetheretherketone (CF-PEEK) composite locking plate with pre-existing data of a titanium-alloy plate when used for fixation of an unstable 2-part fracture of the surgical neck of the humerus. The secondary purpose was to compare the mechanical behaviour of locking bolts and conventional locking cancellous screws. 7 pairs of fresh frozen human humeri were allocated to two equal groups. All specimens were fixed with the CF-PEEK plate. Cancellous screws (PEEK/screw) were compared to locking bolts (PEEK/bolt) for humeral head fixation. Stiffness, fracture gap deflection and ultimate load as well as load before screw perforation of the articular surface were assessed. Results were compared between groups and with pre-existing biomechanical data of a titanium-alloy plate. The CF-PEEK plate featured significantly lower stiffness compared to the titanium-alloy plate (P0.05). The CF-PEEK plate has more elastic properties and significantly increases movement at the fracture site of an unstable proximal humeral fracture model compared to the commonly used titanium-alloy plate. The screw design however does neither affect the constructs primary mechanical behaviour in the constellation tested nor the load before screw perforation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Aortic stiffness and ambulatory blood pressure as predictors of diabetic kidney disease: a competing risks analysis from the Rio de Janeiro Type 2 Diabetes Cohort Study.

    Science.gov (United States)

    Cardoso, Claudia R L; Leite, Nathalie C; Salles, Guilherme C; Ferreira, Marcel T; Salles, Gil F

    2017-10-23

    Diabetic kidney disease (DKD) is a microvascular complication associated with poor control of blood glucose and BP. We aimed to evaluate the predictors of development and progression of DKD in a cohort of high-risk individuals with type 2 diabetes, placing emphasis on ambulatory BP and arterial stiffness. In a prospective study, 629 individuals without advanced renal failure had their renal function evaluated annually over a median follow-up period of 7.8 years. Ambulatory BP was monitored and aortic stiffness was assessed by carotid-femoral pulse wave velocity at baseline. Multivariate competing risks analysis with all-cause mortality, using the Fine and Gray approach, was used to examine the independent predictors of development and progression of DKD, a composite of development or progression of abnormal albuminuria and worsening of renal function (doubling of serum creatinine or progression to end-stage renal disease). At baseline, 197 individuals had DKD. During follow-up, DKD developed or progressed in 195 individuals, abnormal albuminuria developed or progressed in 125 individuals and renal function deteriorated in 91. After adjustments for baseline albuminuria and renal function, age, sex, diabetes duration and use of renin-angiotensin antagonists, poorer control of blood glucose (HR 1.17; 95% CI 0.98, 1.40; p = 0.09 for each 1 SD increment in mean first-year HbA1c), higher ambulatory systolic BP (HR 1.28; 95% CI 1.09, 1.50; p = 0.003, for each 1 SD increase in daytime systolic BP [SBP]) and increased aortic stiffness (HR 1.16; 95% CI 1.00, 1.34; p = 0.05) were independent predictors of development or progression of DKD. At baseline, ambulatory BP was a stronger predictor than BP measured in the clinic. Aortic stiffness predicted abnormal albuminuria development or progression (HR 1.26; 95% CI 1.02, 1.56; p = 0.036) whereas ambulatory BP was a stronger predictor of renal function deterioration (HR 1.32; 95% CI 1.09, 1.60; p = 0.005 for daytime

  14. Development of an experimental model to study the relationship between day-to-day variability in blood pressure and aortic stiffness

    Directory of Open Access Journals (Sweden)

    Camille eBouissou-Schurtz

    2015-12-01

    Full Text Available We aimed to develop an animal model of long-term blood pressure variability (BPV and to investigate its consequences on aortic damage. We hypothesized that day-to-day BPV produced by discontinuous treatment of spontaneously hypertensive rats (SHR by valsartan may increase arterial stiffness. For that purpose, rats were discontinuously treated, 2 days a week, or continuously treated by valsartan (30 mg/kg/d in chow or placebo. Telemetered BP was recorded during 2 minutes every 15 min, 3 days a week during 8 weeks to cover the full BP variations in response to the treatment schedule. Pulse wave velocity (PWV and aortic structure evaluated by immunohistochemistry were investigated in a second set of rats treated under the same conditions. Continuous treatment with valsartan reduced systolic BP (SBP and reversed the aortic structural alterations observed in placebo treated SHR (decrease of medial cross-sectional area. Discontinuous treatment with valsartan decreased SBP to a similar extent but increased the day-to-day blood pressure variability, short term BPV, diastolic blood pressure (DBP and PWV as compared with continuous treatment. Despite no modifications in the elastin/collagen ratio and aortic thickness, an increase in PWV was observed following discontinuous treatment and was associated with a specific accumulation of fibronectin and its av-integrin receptor compared with both groups of rats. Taken together the present results indicate that a discontinuous treatment with valsartan is able to induce a significant increase in day-to-day blood pressure variability coupled to an aortic phenotype close to that observed in hypertension. This experimental model should pave the way for future experimental and clinical studies aimed at assessing how long-term BPV increases aortic stiffness.

  15. Effect of radiotheraphy on impaired aortic elasticity and stiffness in patients with breast cancer.

    Science.gov (United States)

    Kilicaslan, Baris; Piskin, Gonul Demir; Susam, Ibrahim; Dursun, Huseyin; Ozdogan, Oner

    2014-08-01

    We evaluated the effect of radiotherapy (RT) on the elastic properties of the aorta using echocardiography in patients with breast cancer (BC). A total of 105 women with left-sided epidermal growth factor receptor 2 (erb-2) BC were divided into 2 groups, group 1 with patients who did not receive RT and group 2 with patients who received RT. In all patients, echocardiographic examination and serum high-sensitivity C-reactive protein (hs-CRP) levels were determined. A significant decrease in aortic distensibility (AD) and increase in hs-CRP were seen from group 1 to group 2. The AD was inversely correlated with left ventricle diastolic diameter, systolic blood pressure (SBP), left atrial diameter, age, and RT dose. The AD was significantly related to age, SBP, and RT dose. Increased RT dose is significantly correlated with impaired elastic properties that may contribute to the relation of RT and increased rate of cardiovascular events among patients with BC who received RT. © The Author(s) 2013.

  16. Aortic Stiffness and Cardiovascular Risk in Women with Previous Gestational Diabetes Mellitus.

    Directory of Open Access Journals (Sweden)

    Tove Lekva

    Full Text Available Gestational diabetes mellitus (GDM is a significant risk factor for cardiovascular disease (CVD in later life, but the mechanism remains unclear. The aim of the study was to investigate indices of glucose metabolism, dyslipidemia, and arterial stiffness (as measured by pulse wave velocity (PWV, in women with and without a history of GDM, using both the old WHO and new IADPSG diagnostic criteria, at 5 years after the index pregnancy. Dyslipidemia and PWV were used as surrogate markers for CVD risk. The population-based prospective cohort included 300 women from the original STORK study. All participants had an oral glucose tolerance test (OGTT during pregnancy. Five years later, the OGTT was repeated along with dual-energy x-ray absorptiometry, lipid analysis, and PWV analysis. Measurements were compared between those women who did and did not have GDM based on both the WHO and IADPSG criteria. We found that women with GDM based on the old WHO criteria had higher CVD risk at 5 years than those without GDM, with markedly elevated PWV and more severe dyslipidemia (higher triglycerides (TG/HDL cholesterol ratio. After adjusting for known risk factors, the most important predictors for elevated PWV and TG/HDL-C ratio at 5-year follow-up were maternal age, BMI, GDM, systolic blood pressure, and indices of glucose metabolism in the index pregnancy. In conclusion, we found a higher risk for CVD, based on the surrogate markers PWV and TG/HDL-C ratio, at 5-year follow-up in women diagnosed with GDM in the index pregnancy when using the old WHO diagnostic criteria.

  17. Cardiac magnetic resonance based evaluation of aortic stiffness and epicardial fat volume in patients with hypertension, diabetes mellitus, and myocardial infarction.

    Science.gov (United States)

    Homsi, Rami; Sprinkart, Alois M; Gieseke, Juergen; Meier-Schroers, Michael; Yuecel, Seyrani; Fischer, Stefan; Nadal, Jennifer; Dabir, Darius; Luetkens, Julian A; Kuetting, Daniel L; Schild, Hans H; Thomas, Daniel K

    2018-01-01

    Background Aortic stiffness and epicardial fat relate to cardiovascular risk. Their relationship with each other and their role with hypertension, diabetes mellitus (DM), and myocardial infarction (MI) can be evaluated by cardiac magnetic resonance (CMR). Purpose To explore an association between aortic stiffness and epicardial as well as paracardial fat volume (EFV and ParaFV, respectively) in hypertensive patients and to relate the results to the presence of DM and MI. Material and Methods A total of 156 hypertensive and 20 non-hypertensive participants were examined at 1.5 Tesla. A 2D-velocity-encoded sequence was acquired to assess aortic pulse wave velocity (PWV in m/s) as a measure of aortic stiffness. A 3D-Dixon sequence was used to determine EFV and ParaFV. Results PWV correlated with EFV (R = 0.474; P hypertensive controls compared to hypertensive patients. EFV and PWV were significantly higher in diabetic hypertensive patients without MI (n = 19; PWV: 10.4 ± 2.9; EFV: 92.5 ± 19.3) compared to hypertension-only patients (n = 84 [no DM or MI]; EFV: 64.8 ± 25.1, PWV: 9.0 ± 2.6; P hypertensive patients. Both were increased in the presence of DM; however, only EFV was increased in the presence of MI. This may relate to the PWV lowering effect of the antihypertensive medication used by hypertensive patients and underscores the benefit of EFV assessment in this regard.

  18. Aortic and carotid arterial stiffness and epigenetic regulator gene expression changes precede blood pressure rise in stroke-prone Dahl salt-sensitive hypertensive rats.

    Directory of Open Access Journals (Sweden)

    Victoria L Herrera

    Full Text Available Multiple clinical studies show that arterial stiffness, measured as pulse wave velocity (PWV, precedes hypertension and is an independent predictor of hypertension end organ diseases including stroke, cardiovascular disease and chronic kidney disease. Risk factor studies for arterial stiffness implicate age, hypertension and sodium. However, causal mechanisms linking risk factor to arterial stiffness remain to be elucidated. Here, we studied the causal relationship of arterial stiffness and hypertension in the Na-induced, stroke-prone Dahl salt-sensitive (S hypertensive rat model, and analyzed putative molecular mechanisms. Stroke-prone and non-stroke-prone male and female rats were studied at 3- and 6-weeks of age for arterial stiffness (PWV, strain, blood pressure, vessel wall histology, and gene expression changes. Studies showed that increased left carotid and aortic arterial stiffness preceded hypertension, pulse pressure widening, and structural wall changes at the 6-week time-point. Instead, differential gene induction was detected implicating molecular-functional changes in extracellular matrix (ECM structural constituents, modifiers, cell adhesion, and matricellular proteins, as well as in endothelial function, apoptosis balance, and epigenetic regulators. Immunostaining testing histone modifiers Ep300, HDAC3, and PRMT5 levels confirmed carotid artery-upregulation in all three layers: endothelial, smooth muscle and adventitial cells. Our study recapitulates observations in humans that given salt-sensitivity, increased Na-intake induced arterial stiffness before hypertension, increased pulse pressure, and structural vessel wall changes. Differential gene expression changes associated with arterial stiffness suggest a molecular mechanism linking sodium to full-vessel wall response affecting gene-networks involved in vascular ECM structure-function, apoptosis balance, and epigenetic regulation.

  19. Novel Endovascular Management of Proximal Type A (DeBakey II) Aortic Dissection With a Patent Foramen Ovale Occluder.

    Science.gov (United States)

    Yuan, Xun; Mitsis, Andreas; Mozalbat, David; Nienaber, Christoph A

    2017-12-01

    To present a novel endovascular management option that avoids open surgery in selected patients with subacute type A aortic dissection (DeBakey II). A 75-year-old woman with previous infrarenal abdominal aortic aneurysm repaired in 2006 and multiple comorbidities (EURO score II 20.5%) was admitted with chest pain; computed tomography angiography (CTA) showed a new dissection in the ascending aorta just above the right coronary ostium. As the patient was considered unfit to undergo surgery, an endovascular solution was suggested after multidisciplinary team discussion. With a single entry identified, coils were deployed in the false lumen followed by a patent foramen ovale (PFO) occluder placed across the entry tear to seal the cavity. Intraprocedural digital subtraction angiography and transesophageal echocardiography, as well as CTA 3 days postprocedure, confirmed an entirely thrombosed false lumen. The 6-month follow-up CTA demonstrated the PFO occluder firmly in place, shrinkage of the false lumen, and remodeling of the ascending aorta. Interventional management of the false lumen in proximal (type A) dissection is feasible and sustainable. The use of coils and closure devices may present a new, efficient, minimalistic strategy to avoid open surgery in selected cases.

  20. Proximal spleno-renal shunt with retro-aortic left renal vein in a patient with extra-hepatic portal vein obstruction: first case report.

    Science.gov (United States)

    Jain, Sundeep; Kalla, Mukesh; Suleman, Adil; Verma, Alok

    2017-06-02

    Presence of retro-aortic left renal vein poses special challenge in creating spleno-renal shunt potentially increasing the chance of shunt failure. The technical feasibility and successful outcome of splenectomy with proximal spleno-renal shunt (PSRS) with retro-aortic left renal vein is presented for the first time. The patient was treated for portal hypertension and hypersplenism due to idiopathic extra-hepatic portal vein obstruction. A twenty year old male suffering from idiopathic extra-hepatic portal vein obstruction presented with bleeding esophageal varices, portal hypertensive gastropathy, asymptomatic portal biliopathy and symptomatic hypersplenism. As variceal bleeding did not respond to endoscopic and medical treatment, surgical portal decompression was planned. On preoperative contrast enhanced computed tomography retro-aortic left renal vein was detected. Splenectomy with proximal splenorenal shunt with retro-aortic left renal vein was successfully performed by using specific technical steps including adequate mobilisation of retro-aortic left renal vein and per-operative pressure studies. Perioperative course was uneventful and patient is doing well after 3 years of follow up. PSRS is feasible, safe and effective procedure when done with retro-aortic left renal vein for the treatment of portal hypertension related to extra-hepatic portal vein obstruction provided that attention is given to key technical considerations including pressure studies necessary to ensure effective shunt. Present case provides the first evidence that retro-aortic left renal vein can withstand the extra volume of blood flow through the proximal shunt with effective portal decompression so as to treat all the components of extra-hepatic portal vein obstruction without causing renal venous hypertension.

  1. Regular cocaine use is associated with increased systolic blood pressure, aortic stiffness and left ventricular mass in young otherwise healthy individuals.

    Directory of Open Access Journals (Sweden)

    Rebecca Kozor

    Full Text Available BACKGROUND: The cardiovascular impact of cocaine use in otherwise healthy individuals who consider themselves 'social' users is not well established. METHODS/RESULTS: Twenty regular cocaine users and 20 control subjects were recruited by word-of-mouth. Cardiovascular magnetic resonance was performed to assess cardiac and vascular structure and function. Cocaine users had higher systolic blood pressure compared to non-users (134±11 vs 126±11 mmHg, p = 0.036, a finding independent of age, body surface area, smoking and alcohol consumption. Cocaine use was associated with increased arterial stiffness - reflected by reduced aortic compliance (1.3±0.2 vs 1.7±0.5 cm2×10-2.mmHg-1, p = 0.004, decreased distensibility (3.8±0.9 vs 5.1±1.4 mmHg-1.10-3, p = 0.001, increased stiffness index (2.6±0.6 vs 2.1±0.6, p = 0.005, and higher pulse wave velocity (5.1±0.6 vs 4.4±0.6 m.s-1, p = 0.001. This change in aortic stiffness was independent of vessel wall thickness. Left ventricular mass was 18% higher in cocaine users (124±25 vs 105±16 g, p = 0.01, a finding that was independent of body surface area, and left atrial diameter was larger in the user group than controls (3.8±0.6 vs 3.5±0.3 cm, p = 0.04. The increased left ventricular mass, systolic blood pressure and vascular stiffness measures were all associated with duration and/or frequency of cocaine use. No late gadolinium enhancement or segmental wall motion abnormalities were seen in any of the subjects. CONCLUSIONS: Compared with the non-user control cohort, cocaine users had increased aortic stiffness and systolic blood pressure, associated with greater left ventricular mass. These measures are all well known risk factors for premature cardiovascular events, highlighting the dangers of cocaine use, even in a 'social' setting, and have important public health implications.

  2. Optimizing finite element predictions of local subchondral bone structural stiffness using neural network-derived density-modulus relationships for proximal tibial subchondral cortical and trabecular bone.

    Science.gov (United States)

    Nazemi, S Majid; Amini, Morteza; Kontulainen, Saija A; Milner, Jaques S; Holdsworth, David W; Masri, Bassam A; Wilson, David R; Johnston, James D

    2017-01-01

    Quantitative computed tomography based subject-specific finite element modeling has potential to clarify the role of subchondral bone alterations in knee osteoarthritis initiation, progression, and pain. However, it is unclear what density-modulus equation(s) should be applied with subchondral cortical and subchondral trabecular bone when constructing finite element models of the tibia. Using a novel approach applying neural networks, optimization, and back-calculation against in situ experimental testing results, the objective of this study was to identify subchondral-specific equations that optimized finite element predictions of local structural stiffness at the proximal tibial subchondral surface. Thirteen proximal tibial compartments were imaged via quantitative computed tomography. Imaged bone mineral density was converted to elastic moduli using multiple density-modulus equations (93 total variations) then mapped to corresponding finite element models. For each variation, root mean squared error was calculated between finite element prediction and in situ measured stiffness at 47 indentation sites. Resulting errors were used to train an artificial neural network, which provided an unlimited number of model variations, with corresponding error, for predicting stiffness at the subchondral bone surface. Nelder-Mead optimization was used to identify optimum density-modulus equations for predicting stiffness. Finite element modeling predicted 81% of experimental stiffness variance (with 10.5% error) using optimized equations for subchondral cortical and trabecular bone differentiated with a 0.5g/cm(3) density. In comparison with published density-modulus relationships, optimized equations offered improved predictions of local subchondral structural stiffness. Further research is needed with anisotropy inclusion, a smaller voxel size and de-blurring algorithms to improve predictions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Aortic stiffness is associated with the central retinal arteriolar equivalent and retinal vascular fractal dimension in a population along the southeastern coast of China.

    Science.gov (United States)

    Lin, Fan; Zhu, Pengli; Huang, Feng; Li, Qiaowei; Yuan, Yin; Gao, Zhonghai; Yu, Peng; Lin, Jing; Chen, Falin

    2015-05-01

    The objective of this study was to evaluate the association of the central retinal arteriolar equivalent (CRAE) and the retinal vascular fractal dimension, two quantitative parameters that reflect microcirculation, with aortic stiffness. In this cross-sectional study, we identified the cardiovascular risk factors in 2169 subjects using a health questionnaire, physical examinations and laboratory examinations. We evaluated the aortic stiffness using noninvasive brachial-ankle pulse wave velocity (baPWV) and assessed the microcirculatory alterations with CRAE and retinal vascular fractal dimension, which were measured using fundus photography and semiautomatic quantitative software, respectively. The increase in baPWV (Q1-Q4) correlated with an increased likelihood of the central retinal artery narrowing and a reduction in the retinal vascular fractal dimension. Further adjustment of the cardiovascular risk factors diminished the association between baPWV and CRAE, but increased the association between baPWV and retinal vascular fractal dimension. Elevated baPWV correlates with reduced CRAE and retinal vascular fractal dimension. Such a finding supports macrocirculation- and microcirculation-associated hypotheses.

  4. Medium-Term Outcomes Following Endovascular Repair of Infrarenal Abdominal Aortic Aneurysms with an Unfavourable Proximal Neck

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Prakash, E-mail: prakash.2.saha@kcl.ac.uk; Hughes, John, E-mail: johnhughes387@rocketmail.com; Patel, Ashish S., E-mail: ashish.s.patel@kcl.ac.uk; Donati, Tommaso, E-mail: tommaso.donati@gstt.nhs.uk; Sallam, Morad, E-mail: morad.sallam@gstt.nhs.uk; Patel, Sanjay D., E-mail: sanjay.patel@gstt.nhs.uk; Bell, Rachel E. [King’s Health Partners, Department of Vascular Surgery, Guy’s and St. Thomas’ Hospitals, NHS Foundation Trust (United Kingdom); Katsanos, Konstantinos, E-mail: katsanos@med.upatras.gr [King’s Health Partners, Department of Interventional Radiology, Guy’s and St. Thomas’ Hospitals, NHS Foundation Trust (United Kingdom); Modarai, Bijan, E-mail: bijan.modarai@kcl.ac.uk; Zayed, Hany A., E-mail: hany.zayed@gstt.nhs.uk [King’s Health Partners, Department of Vascular Surgery, Guy’s and St. Thomas’ Hospitals, NHS Foundation Trust (United Kingdom)

    2015-08-15

    PurposeThe purpose of this study was to evaluate medium-term outcomes following endovascular repair of abdominal aortic aneurysms (EVAR) with unfavourable neck anatomy using stent grafts with a 36 mm or larger proximal diameter.Materials and MethodsA retrospective review of 27 patients who underwent elective EVAR between 2006 and 2008 using a stent graft with a 36 mm or larger proximal diameter was carried out. All patients had computed tomography angiography (CTA) for procedure planning, and detailed assessment of the aneurysm neck was performed using a three-dimensional CTA workstation. Patients were followed up with CTA at 3 and 12 months and annual duplex thereafter.ResultsThe median aneurysm diameter was 7 cm, and the median aneurysm neck diameter was 31 mm. Cook Zenith stent grafts were used in all patients, with a proximal diameter of 36 mm (n = 25) and 40 mm (n = 2). Primary and assisted primary technical success rates were 74 and 93 %, respectively. The follow-up period ranged from 62 to 84 months, with a median of 72 months. 15 patients died during follow-up. Two patients died from aortic rupture, and the remaining patients died from cardiac disease (n = 4), chest sepsis (n = 6), cancer (n = 2) and renal failure (n = 1). Complications included type I endoleak (n = 5), limb occlusion (n = 2), limb stenosis (n = 2), limb kinking (n = 1), dissection of an artery (n = 1), occlusion of a femorofemoral cross-over graft (n = 1) and poor attachment of a distal limb (n = 1).ConclusionsEVAR using stent grafts in the presence of an unfavourable neck has a high risk of complications. Medium-term survival in this group is low but mainly due to patient co-morbidities.

  5. Comprehensive assessment of biventricular function and aortic stiffness in athletes with different forms of training by three-dimensional echocardiography and strain imaging.

    Science.gov (United States)

    Vitarelli, Antonio; Capotosto, Lidia; Placanica, Giuseppe; Caranci, Fiorella; Pergolini, Mario; Zardo, Francesco; Martino, Francesco; De Chiara, Stefania; Vitarelli, Massimo

    2013-10-01

    Previous studies have shown distinct models of cardiac adaptations to the training in master athletes and different effects of endurance and strength-training on cardiovascular function. We attempted to assess left-ventricular (LV) function, aortic (Ao) function, and right-ventricular (RV) function in athletes with different forms of training by using three-dimensional (3D) echocardiography, tissue Doppler imaging (TDI) and speckle-tracking imaging (STI). We examined 35 male marathon runners (endurance-trained athletes, ETA), 35 powerlifting athletes (strength-trained athletes, STA), 35 martial arts athletes (mixed-trained athletes, MTA), and 35 sedentary untrained healthy men (controls, CTR). Two-dimensional and three-dimensional echocardiography were performed for the assessment of LV and RV systolic/diastolic function. LV and RV longitudinal strain (LS) and LV torsion (LVtor) were determined using STI (EchoPAC BT11, GE-Ultrasound). Maximum velocity of systolic wall expansion peaks (AoSvel) was determined using TDI. ETA experienced LV eccentric hypertrophy with increased 3D LV end-diastolic volume and mass and significant increase in peak systolic apical rotation and LVtor. In all groups of athletes, RV-LS was reduced at rest and improved after exercise. AoSvel was significantly increased in ETA and MTA and significantly decreased in STA compared with CTR. There were good correlations between LV remodelling and aortic stiffness values. Multivariate analysis showed aortic wall velocities to be independently related to LV mass index. In strength-trained, endurance-trained, and mixed-trained athletes, ventricular and vascular response assessed by 3DE, TDI, and STI underlies different adaptations of LV, RV, and aortic indexes.

  6. Relative Importance of Aortic Stiffness and Volume as Predictors of Treatment-Induced Improvement in Left Ventricular Mass Index in Dialysis.

    Directory of Open Access Journals (Sweden)

    Panagiotis I Georgianos

    Full Text Available This study aimed to explore the relative contribution of aortic stiffness and volume in treatment-induced change of left ventricular mass in dialysis. Hypertension in Hemodialysis Patients Treated with Atenolol or Lisinopril trial compared the effect of lisinopril versus atenolol in reducing left ventricular mass index; 179 patients with echo measurements of aortic pulse wave velocity and left ventricular mass at baseline were included. In unadjusted analysis, overall reductions of 26.24 g/m2 (95% CI: -49.20, -3.29 and 35.67 g/m2 (95% CI: -63.70, -7.64 in left ventricular mass index were noted from baseline to 6 and 12 months respectively. Volume control emerged as an important determinant of regression of left ventricular mass index due to the following reasons: (i additional control for change in ambulatory systolic blood pressure mitigated the reduction in left ventricular mass index in the statistical model above [6-month visit: -18.6 g/m2 (95% CI: -43.7, 6.5; 12-month visit: -22.1 g/m2 (95% CI: -52.2, 8.0] (ii regression of left ventricular hypertrophy was primarily due to reduction in left ventricular chamber and not wall thickness and (iii adjustment for inferior vena cava diameter (as a proxy for volume removed the effect of time on left ventricular mass index reduction [6-month visit: -6.6 g/m2 (95% CI: (-41.6, 28.4; 12-month visit: 0.6 g/m2 (95% CI: -39.5, 40.7]. In contrast, aortic pulse wave velocity was neither a determinant of baseline left ventricular mass index nor predictor of its reduction. Among dialysis patients, ambulatory systolic pressure, a proxy for volume expansion, but not aortic stiffness is more important predictor of reduction in left ventricular mass index. Improving blood pressure control via adequate volume management appears as an effective strategy to improve left ventricular hypertrophy in dialysis.

  7. Perioperative and mid-term results of endovascular management of complicated type B aortic dissection using a proximal thoracic endoprosthesis and selective distal bare stenting.

    Science.gov (United States)

    Kische, Stephan; D'Ancona, Giuseppe; Belu, Ioan Christian; Stoeckicht, Yannik; Agma, Umut; Ortak, Jasmin; Ince, Hüseyin

    2015-10-01

    To present results of endovascular treatment of complicated type B aortic dissection. Patients with acutely complicated type B aortic dissection extending from the left sub-clavian artery to the abdominal aorta were treated. The strategy involved the placement of a covered endoprosthesis to seal the primary entry tear and, in cases where malperfusion persisted, distal extension with uncovered stents, to enhance true lumen (TL) expansion and reperfusion of the ischaemic arterial branches originating from the TL. Thirty-five patients were included. Mean age was 63.1 (37-79) years and malperfusion syndrome occurred in 71.4%. Average aortic coverage with endoprostheses was 220.6 mm (136-355 mm). In 17 cases (48.5%), distal extension with uncovered stents was necessary. Thirty-day major morbidity was 28.5%, and mortality 2.8%. At follow-up (25.6 ± 19.5 months; 4-73 months), overall mortality was 15.2%, and aortic mortality 12.1%. Additional aortic intervention was necessary in 18.2%. Although patients undergoing distal extension with bare metal stents suffered most often from preoperative malperfusion, no significant differences were noted in the 30-day and follow-up clinical results. Follow-up angio-computed tomography showed complete thrombosis of the false lumen in the proximal half of the thoracic aorta in 76.4%. Patients treated with bare stents had significantly larger aortic TL sizes, at the different abdominal aorta levels. In patients with complicated type B aortic dissection, tailored elongation with uncovered stents is a safe treatment of persistent malperfusion. Although the results presented are encouraging, randomized data and a longer follow-up are required to confirm benefits and complications of this strategy. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  8. Better Axial Stiffness of a Bicortical Screw Construct Compared to a Cable Construct for Comminuted Vancouver B1 Proximal Femoral Fractures.

    Science.gov (United States)

    Griffiths, Jamie T; Taheri, Arash; Day, Robert E; Yates, Piers J

    2015-12-01

    The aim of this study was to biomechanically evaluate the Locking attachment plate (LAP) construct in comparison to a Cable plate construct, for the fixation of periprosthetic femoral fractures after cemented total hip arthroplasty. Each construct incorporated a locking compression plate with bi-cortical locking screws for distal fixation. In the Cable construct, 2 cables and 2 uni-cortical locking screws were used for proximal fixation. In the LAP construct, the cables were replaced by a LAP with 4 bi-cortical locking screws. The LAP construct was significantly stiffer than the cable construct under axial load with a bone gap (P=0.01). The LAP construct offers better axial stiffness compared to the cable construct in the fixation of comminuted Vancouver B1 proximal femoral fractures. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

  9. The usefulness of a single arm cuff oscillometric method (Arteriograph) to assess changes in central aortic blood pressure and arterial stiffness by antihypertensive treatment: results from the Doxazosin-Ramipril Study.

    Science.gov (United States)

    Jekell, Andreas; Kahan, Thomas

    2017-10-26

    Inhibition of the renin-angiotensin system may have effects on vascular structure and function beyond the effects on blood pressure (BP) reduction. We studied the ability of a single arm cuff oscillometric method (Arteriograph, TensioMed, Hungary) to assess effects of antihypertensive treatment on BP and arterial stiffness. Furthermore, this technique was compared to pulse wave analysis and applanation tonometry (SphygmoCor, AtCor Medical, Australia). Brachial and aortic BP, augmentation index (AIx), and carotid-femoral pulse wave velocity (PWV) was simultaneously assessed by both techniques in 71 untreated hypertensive patients. Thereafter, 58 completed double-blind randomized treatment for 12 weeks with ramipril or doxazosin. Treatment (assessed by the Arteriograph) reduced aortic more than brachial systolic BP (-13.2 vs. -11.2 mm Hg; p = .002) and improved all indices of arterial stiffness. This greater reduction in aortic to brachial systolic BP was more marked by ramipril than by doxazosin (-20.9 and -17.1 vs. -4.3 and -4.2 mm Hg; p = .006), with a similar trend for AIx (-6.2 vs. -2.2%; p = .058). Both devices showed correlations for aortic and brachial systolic and diastolic BP and AIx (r = 0.75-0.86, all p < .001), while agreement for PWV was weaker (r = 0.28; p = .043). The Arteriograph generally recorded higher values for aortic BP and AIx than the SphygmoCor. Antihypertensive treatment reduced aortic systolic BP more than brachial BP and improved arterial stiffness. Blocking the renin-angiotensin system may have additional effects beyond BP reduction. We demonstrate the feasibility of the Arteriograph to monitor changes in BP and arterial stiffness by treatment.

  10. Aortic Blood Flow Reversal Determines Renal Function: Potential Explanation for Renal Dysfunction Caused by Aortic Stiffening in Hypertension.

    Science.gov (United States)

    Hashimoto, Junichiro; Ito, Sadayoshi

    2015-07-01

    Aortic stiffness determines the glomerular filtration rate (GFR) and predicts the progressive decline of the GFR. However, the underlying pathophysiological mechanism remains obscure. Recent evidence has shown a close link between aortic stiffness and the bidirectional (systolic forward and early diastolic reverse) flow characteristics. We hypothesized that the aortic stiffening-induced renal dysfunction is attributable to altered central flow dynamics. In 222 patients with hypertension, Doppler velocity waveforms were recorded at the proximal descending aorta to calculate the reverse/forward flow ratio. Tonometric waveforms were recorded to measure the carotid-femoral (aortic) and carotid-radial (peripheral) pulse wave velocities, to estimate the aortic pressure from the radial waveforms, and to compute the aortic characteristic impedance. In addition, renal hemodynamics was evaluated by duplex ultrasound. The estimated GFR was inversely correlated with the aortic pulse wave velocity, reverse/forward flow ratio, pulse pressure, and characteristic impedance, whereas it was not correlated with the peripheral pulse wave velocity or mean arterial pressure. The association between aortic pulse wave velocity and estimated GFR was independent of age, diabetes mellitus, hypercholesterolemia, and antihypertensive medication. However, further adjustment for the aortic reverse/forward flow ratio and pulse pressure substantially weakened this association, and instead, the reverse/forward flow ratio emerged as the strongest determinant of estimated GFR (P=0.001). A higher aortic reverse/forward flow ratio was also associated with lower intrarenal forward flow velocities. These results suggest that an increase in aortic flow reversal (ie, retrograde flow from the descending thoracic aorta toward the aortic arch), caused by aortic stiffening and impedance mismatch, reduces antegrade flow into the kidney and thereby deteriorates renal function. © 2015 American Heart Association

  11. A health profile associated with excessive alcohol use independently predicts aortic stiffness over 10 years in black South Africans.

    Science.gov (United States)

    Maritz, Melissa; Fourie, Carla M T; van Rooyen, Johannes M; Kruger, Iolanthe M; Schutte, Aletta E

    2017-11-01

    Black populations exhibit higher arterial stiffness than whites and suffer a disproportionate burden of cardiovascular disease. It is therefore important to identify modifiable health behaviours predicting large artery stiffness in blacks. We examined whether traditional cardiovascular risk factors and health behaviours of black South Africans predict large artery stiffness 10 years later. We included 650 HIV-free participants (32.8% men) and collected data in rural and urban areas of the North West Province in 2005 and 2015. We collected questionnaire data, anthropometry, blood pressure and determined cardiometabolic and inflammatory markers from blood samples. We measured carotid-femoral pulse wave velocity (PWV) at follow-up. A total of 25.3% of our population, aged 65 ± 9.57 years, had a PWV exceeding 10 m/s. In multivariable-adjusted regression analyses, the strongest predictors of PWV were mean arterial pressure, age and heart rate (all P alcohol use (β = 0.11, P = 0.018) and plasma glucose (β = 0.08 P = 0.023) associated positively with PWV at follow-up. We found a negative association between PWV and BMI (β = -0.15, P = 0.001), and no associations with sex, smoking, inflammatory markers, lipids, liver enzymes or antihypertensive medication. When replacing self-reported alcohol with gamma-glutamyltransferase, the latter associated positively with PWV (β = 0.09, P = 0.023). A health profile associated with excessive alcohol use, including an urban setting, elevated plasma glucose and lower BMI predicts large artery stiffness independently of age and blood pressure in black South Africans over 10 years. This observation prompts urgent public health strategies to target alcohol overuse.

  12. Keeping the golden mean: plant stiffness and anatomy as proximal factors driving endophytic oviposition site selection in a dragonfly.

    Science.gov (United States)

    Matushkina, Natalia; Lambret, Philippe; Gorb, Stanislav

    2016-12-01

    Oviposition site selection is a crucial component of habitat selection in dragonflies. The presence of appropriate oviposition plants at breeding waters is considered to be one of the key habitat determinants for species laying eggs endophytically. Thus, Lestes macrostigma, a species which is regarded as threatened in Europe because of its highly disjunct distribution, typically prefers to lay eggs in the sea club rush Bolboschoenus maritimus. However, little is known about how the anatomical and mechanical properties of plant tissues determine the choice of L. macrostigma females. We examined green shoots of six plant species used by L. macrostigma for oviposition, either in the field (actual oviposition plants) or under experimental conditions (potential oviposition plants), to analyse anatomical and mechanical properties of shoots in a framework of known preferences regarding plant substrates for oviposition. As expected, the anatomy of shoots differed between representatives of two plant families, Cyperaceae and Juncaceae, most essentially in the distribution of supporting bundles and the presence of large aeriferous cavities that may affect egg placing within a shoot. The force necessary to puncture the tested plant samples ranged from 360 to 3298 mN, and their local stiffness ranged from 777 to 3363N/m. We show that the shoots of B. maritimus, the plant most preferred by L. macrostigma, have intermediate characteristics regarding both the stiffness and specific anatomical characteristics. The bending stiffness of the ovipositor in L. macrostigma was estimated as 1414N/m, one of the highest values recorded for zygopteran dragonflies so far. The ecological and behavioural implications of plant choice mechanisms in L. macrostigma are discussed in the context of the disjunct distribution of this species. Copyright © 2016 Elsevier GmbH. All rights reserved.

  13. Beyond type 2 diabetes, obesity and hypertension: an axis including sleep apnea, left ventricular hypertrophy, endothelial dysfunction, and aortic stiffness among Mexican Americans in Starr County, Texas.

    Science.gov (United States)

    Hanis, Craig L; Redline, Susan; Cade, Brian E; Bell, Graeme I; Cox, Nancy J; Below, Jennifer E; Brown, Eric L; Aguilar, David

    2016-06-08

    There is an increasing appreciation for a series of less traditional risk factors that should not be ignored when considering type 2 diabetes, obesity, hypertension, and cardiovascular disease. These include aortic stiffness, cardiac structure, impaired endothelial function and obstructive sleep apnea. They are associated to varying degrees with each disease categorization and with each other. It is not clear whether they represent additional complications, concomitants or antecedents of disease. Starr County, Texas, with its predominantly Mexican American population has been shown previously to bear a disproportionate burden of the major disease categories, but little is known about the distribution of these less traditional factors. Type 2 diabetes, obesity and hypertension frequencies were determined through a systematic survey of Starr County conducted from 2002 to 2006. Individuals from this examination and an enriched set with type 2 diabetes were re-examined from 2010 to 2014 including assessment of cardiac structure, sleep apnea, endothelial function and aortic stiffness. Individual and combined frequencies of these inter-related (i.e., axis) conditions were estimated and associations evaluated. Household screening of 5230 individuals aged 20 years and above followed by direct physical assessment of 1610 identified 23.7 % of men and 26.7 % of women with type 2 diabetes, 46.2 and 49.5 % of men and women, respectively with obesity and 32.1 and 32.4 % with hypertension. Evaluation of pulse wave velocity, left ventricular mass, endothelial function and sleep apnea identified 22.3, 12.7, 48.6 and 45.2 % of men as having "at risk" values for each condition, respectively. Corresponding numbers in women were 16.0, 17.9, 23.6 and 28.8 %. Cumulatively, 88 % of the population has one or more of these while 50 % have three or more. The full axis of conditions is high among Mexican Americans in Starr County, Texas. Individual and joint patterns suggest a genesis well

  14. Influence of Distal Resistance and Proximal Stiffness on Hemodynamics and RV Afterload in Progression and Treatments of Pulmonary Hypertension: A Computational Study with Validation Using Animal Models

    Directory of Open Access Journals (Sweden)

    Zhenbi Su

    2013-01-01

    Full Text Available We develop a simple computational model based on measurements from a hypoxic neonatal calf model of pulmonary hypertension (PH to investigate the interplay between vascular and ventricular measures in the setting of progressive PH. Model parameters were obtained directly from in vivo and ex vivo measurements of neonatal calves. Seventeen sets of model-predicted impedance and mean pulmonary arterial pressure (mPAP show good agreement with the animal measurements, thereby validating the model. Next, we considered a predictive model in which three parameters, PVR, elastic modulus (EM, and arterial thickness, were varied singly from one simulation to the next to study their individual roles in PH progression. Finally, we used the model to predict the individual impacts of clinical (vasodilatory and theoretical (compliance increasing PH treatments on improving pulmonary hemodynamics. Our model (1 displayed excellent patient-specific agreement with measured global pulmonary parameters; (2 quantified relationships between PVR and mean pressure and PVS and pulse pressure, as well as studiying the right ventricular (RV afterload, which could be measured as a hydraulic load calculated from spectral analysis of pulmonary artery pressure and flow waves; (3 qualitatively confirmed the derangement of vascular wall shear stress in progressive PH; and (4 established that decreasing proximal vascular stiffness through a theoretical treatment of reversing proximal vascular remodeling could decrease RV afterload.

  15. Whole exome sequencing implicates an INO80D mutation in a syndrome of aortic hypoplasia, premature atherosclerosis, and arterial stiffness.

    Science.gov (United States)

    Shameer, Khader; Klee, Eric W; Dalenberg, Angela K; Kullo, Iftikhar J

    2014-10-01

    Massively parallel, high-throughput sequencing technology is helping to generate new insights into the genetic basis of human diseases. We used whole exome sequencing to identify the mutation underlying a syndrome affecting 2 siblings with aortic hypoplasia, calcific atherosclerosis, systolic hypertension, and premature cataract. Exonic regions were captured and sequenced using a next-generation sequencing platform to generate 100 bases paired-end reads. A computational genomic data analysis pipeline was used to perform quality control, align reads to a reference genome, and identify genetic variants; findings were confirmed using a different exome analyses pipeline. The 2 siblings were homozygous for a rare missense mutation (Ser818Cys) in INO80D, a subunit of the human INO80 chromatin remodeling complex. Homozygosity mapping and Sanger sequencing confirmed that the mutation is located in one of the runs of homozygosity on chromosome 2. INO80D encodes a key subunit of the human IN080 complex, a multiprotein complex involved in DNA binding, chromatin modification, organization of chromosome structure, and ATP-dependent nucleosome sliding. By introducing a new disulphide-bond in the protein product and also disrupting the composition of low-complexity regions, the Ser818Cys mutation may affect INO80D function, protein-protein interactions, and chromatin remodeling. Our findings suggest a link between the Ser818Cys mutation in INO80D, a subunit of the human INO80 chromatin remodeling complex, and accelerated arterial aging. © 2014 American Heart Association, Inc.

  16. The Effect Of Supraphysiologic Blood Pressure on Traumatic Brain Injury and Proximal Tissue Beds During Resuscitative Balloon Occlusion of the Aorta and Variable Aortic Control in a Porcine Model (Sus scrofa) of Polytrauma.

    Science.gov (United States)

    2017-04-27

    Supraphysiologic Blood Pressure On Traumatic Brain Injury And Proximal Tissue Beds During Resuscitative Balloon Occlusion Of The Aorta And Variable Aortic...Mandatory) The Effect of REBOA, Partial Aortic Occlusion and Aggressive Blood Transfusion on Traumatic Brain Injury in a Swine Polytrauma Model...Objectives: Despite clinical reports of poor outcomes, the degree to which REBOA exacerbates traumatic brain injury (TBI) is not known. We hypothesized that

  17. Prognostic value of aortic stiffness and calcification for cardiovascular events and mortality in dialysis patients: outcome of the calcification outcome in renal disease (CORD) study

    DEFF Research Database (Denmark)

    Verbeke, Francis; Van Biesen, Wim; Honkanen, Eero

    2011-01-01

    BACKGROUND AND OBJECTIVES: Radiographic calcification and arterial stiffness each individually are predictive of outcome in dialysis patients. However, it is unknown whether combined assessment of these intermediate endpoints also provides additional predictive value. DESIGN, SETTING, PARTICIPANT...

  18. Arterial stiffness

    Directory of Open Access Journals (Sweden)

    Ursula Quinn

    2012-09-01

    Full Text Available Measurements of biomechanical properties of arteries have become an important surrogate outcome used in epidemiological and interventional cardiovascular research. Structural and functional differences of vessels in the arterial tree result in a dampening of pulsatility and smoothing of blood flow as it progresses to capillary level. A loss of arterial elastic properties results a range of linked pathophysiological changes within the circulation including increased pulse pressure, left ventricular hypertrophy, subendocardial ischaemia, vessel endothelial dysfunction and cardiac fibrosis. With increased arterial stiffness, the microvasculature of brain and kidneys are exposed to wider pressure fluctuations and may lead to increased risk of stroke and renal failure. Stiffening of the aorta, as measured by the gold-standard technique of aortic Pulse Wave Velocity (aPWV, is independently associated with adverse cardiovascular outcomes across many different patient groups and in the general population. Therefore, use of aPWV has been proposed for early detection of vascular damage and individual cardiovascular risk evaluation and it seems certain that measurement of arterial stiffness will become increasingly important in future clinical care. In this review we will consider some of the pathophysiological processes that result from arterial stiffening, how it is measured and factors that may drive it as well as potential avenues for therapy. In the face of an ageing population where mortality from atheromatous cardiovascular disease is falling, pathology associated with arterial stiffening will assume ever greater importance. Therefore, understanding these concepts for all clinicians involved in care of patients with cardiovascular disease will become vital.

  19. Is chronic obstructive pulmonary disease associated with increased arterial stiffness?

    DEFF Research Database (Denmark)

    Janner, Julie H; McAllister, David A; Godtfredsen, Nina S

    2012-01-01

    We hypothesize that airflow limitation is associated with increasing arterial stiffness and that having COPD increases a non-invasive measure of arterial stiffness - the aortic augmentation index (AIx) - independently of other CVD risk factors....

  20. Mitochondrial oxidative stress in aortic stiffening with age: the role of smooth muscle cell function.

    Science.gov (United States)

    OBJECTIVE: Age-related aortic stiffness is an independent risk factor for cardiovascular diseases. Although oxidative stress is implicated in aortic stiffness, the underlying molecular mechanisms remain unelucidated. Here, we examined the source of oxidative stress in aging and i...

  1. Changes in aortic pulse wave velocity of four thoracic aortic stent grafts in an ex vivo porcine model

    NARCIS (Netherlands)

    de Beaufort, Hector W L; Coda, Margherita; Conti, Michele; van Bakel, Theodorus M J; Nauta, Foeke J H; Lanzarone, Ettore; Moll, Frans L|info:eu-repo/dai/nl/070246882; van Herwaarden, Joost A|info:eu-repo/dai/nl/304814733; Auricchio, Ferdinando; Trimarchi, Santi

    2017-01-01

    OBJECTIVES: Thoracic endovascular aortic repair (TEVAR) has been shown to lead to increased aortic stiffness. The aim of this study was to investigate the effect of stent graft type and stent graft length on aortic stiffness in a controlled, experimental setting. METHODS: Twenty porcine thoracic

  2. Proximal Aortic Distensibility is an Independent Predictor of All-cause Mortality and Incident Cardiovascular Events in the Multi-Ethnic Study of Atherosclerosis

    Science.gov (United States)

    Redheuil, Alban; Wu, Colin O.; Kachenoura, Nadjia; Ohyama, Yoshiaki; Yan, Raymond T.; Bertoni, Alain G.; Hundley, Gregory W.; Duprez, Daniel A.; Jacobs, David R.; Daniels, Lori B.; Darwin, Christine; Sibley, Christopher; Bluemke, David A.; Lima, Joao A.C.

    2014-01-01

    BACKGROUND The predictive value of ascending aortic distensibility (AAD) for mortality and hard cardiovascular disease (CVD) events is not fully established. OBJECTIVES We sought to assess the utility of AAD to predict mortality and incident CVD events beyond conventional risk factors in the Multi-Ethnic Study of Atherosclerosis (MESA). METHODS AAD was measured with magnetic resonance imaging at baseline in 3,675 MESA participants free of overt CVD. Cox proportional-hazards regression was used to evaluate risk of death, heart failure (HF), and incident CVD in relation to AAD, CVD risk factors, indices of subclinical atherosclerosis, and Framingham risk score. RESULTS There were 246 deaths and 171 hard CVD (myocardial infarction, resuscitated cardiac arrest, stroke and cardiovascular [CV] death) and 88 HF events over a median 8.5-year follow-up. Decreased AAD was associated with increased all-cause mortality with a hazard ratio (HR) for the first verus fifth quintile of AAD of 2.7 (p = 0.008) independent of age, sex, ethnicity, other CVD risk factors, and indices of subclinical atherosclerosis. Overall, subjects with lowest AAD had an independent 2-fold risk of hard CVD events. Decreased AAD was associated with CV events in low-to-intermediate CVD risk individuals with an HR for the first quintile of AAD of 5.3 (p = 0.03) as well as with incident HF but not after full adjustment. CONCLUSIONS Decreased proximal aorta distensibility significantly predicts all-cause mortality and hard CV events among individuals without overt CVD. AAD may help refine risk stratification, especially among asymptomatic, low-to-intermediate risk individuals. PMID:25524341

  3. Aorfix™ device for abdominal aortic aneurysm with challenging anatomy.

    Science.gov (United States)

    Sbarzaglia, P; Grattoni, C; Oshoala, K; Castriota, F; D'Alessandro, G; Cremonesi, A

    2014-02-01

    Anatomical characteristics of abdominal aortic aneurysms (AAA) are the most critical factors for successful endovascular aortic repair (EVAR). Of these, severe proximal aortic neck angulation and iliac axis tortuosity increase the complexity of EVAR. Neck angulation seems to have a pivotal potential for fixation failure, a situation that may lead to complications, including endoleak and late rupture. Bench-test studies identified that the relative stiffness of a stent-graft was responsible for its inability to conform to neck angulation, therefore creating leaks through gaps between the stent graft and the neck. Aorfix™ stent graft (Lombard Medical, Didcot, UK) is a flexible stent-graft designed and manufactured with the purpose of overcoming the issue of stent-graft stiffness. Many studies have shown good results in term of procedural success and mid-term type-I endoleak. PYTHAGORAS trial evaluated mainly patients with highly angulated infrarenal neck and showed that high performance of Aorfix™ stent graft did not present any significant difference between neck >60° and <60°. In the series of 27 patients treated at our Institution we had a primary technical success of 96.3% and an assisted primary technical success of 100%. In this review we will analyze the available data in literature regarding Aorfix™ stent graft and will discuss the outcome of the patients treated with Aorfix™ stent graft at our centre.

  4. Biomechanical and biochemical properties of the thoracic aorta in warmblood horses, Friesian horses, and Friesians with aortic rupture.

    Science.gov (United States)

    Saey, Veronique; Famaey, Nele; Smoljkic, Marija; Claeys, Erik; van Loon, Gunther; Ducatelle, Richard; Ploeg, Margreet; Delesalle, Catherine; Gröne, Andrea; Duchateau, Luc; Chiers, Koen

    2015-11-18

    Thoracic aortic rupture and aortopulmonary fistulation are rare conditions in horses. It mainly affects Friesian horses. Intrinsic differences in biomechanical properties of the aortic wall might predispose this breed. The biomechanical and biochemical properties of the thoracic aorta were characterized in warmblood horses, unaffected Friesian horses and Friesians with aortic rupture in an attempt to unravel the underlying pathogenesis of aortic rupture in Friesian horses. Samples of the thoracic aorta at the ligamentum arteriosum (LA), mid thoracic aorta (T1) and distal thoracic aorta (T2) were obtained from Friesian horses with aortic rupture (A), nonaffected Friesian (NA) and warmblood horses (WB). The biomechanical properties of these samples were determined using uniaxial tensile and rupture assays. The percentages of collagen and elastin (mg/mg dry weight) were quantified. Data revealed no significant biomechanical nor biochemical differences among the different groups of horses. The distal thoracic aorta displayed an increased stiffness associated with a higher collagen percentage in this area and a higher load-bearing capacity compared to the more proximal segments. Our findings match reported findings in other animal species. Study results did not provide evidence that the predisposition of the Friesian horse breed for aortic rupture can be attributed to altered biomechanical properties of the aortic wall.

  5. Aortic dissection

    Science.gov (United States)

    ... made in the chest or abdomen. Endovascular aortic repair. This surgery is done without any major surgical ... needed. If the heart arteries are involved, a coronary bypass is also performed. Outlook ... aneurysm - dissecting; Chest pain - aortic dissection; Thoracic aortic aneurysm - ...

  6. Management of acute aortic dissection.

    Science.gov (United States)

    Nienaber, Christoph A; Clough, Rachel E

    2015-02-28

    A new appraisal of the management of acute aortic dissection is timely because of recent developments in diagnostic strategies (including biomarkers and imaging), endograft design, and surgical treatment, which have led to a better understanding of the epidemiology, risk factors, and molecular nature of aortic dissection. Although open surgery is the main treatment for proximal aortic repair, use of endovascular management is now established for complicated distal dissection and distal arch repair, and has recently been discussed as a pre-emptive measure to avoid late complications by inducing aortic remodelling. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. [Acute aortic syndrome].

    Science.gov (United States)

    Nienaber, Christoph A

    2016-06-01

    Acute aortic syndrome is the common denominator for acute events to the aortic wall and encompasses dissection of the aorta, intramural hematoma, formation of aortic ulcers and trauma to the aorta with an annual incidence of up to 35 cases/100.000 between 65 and 75 years of age. Both, inflammation and/or microtrauma at the level of the aortic media layer, and a genetic disposition are promoting elements of AAS, while the extent and anatomic involvement of the ascending aorta call for either surgical resection/repair in the proximal part of the aorta, or an endovascular solution for pathologies in the distal aorta; in all cases of dissection (regardless of location) reconstruction/realignment has been proven to portend better long-term outcomes (in addition to medical management of blood pressure). © Georg Thieme Verlag KG Stuttgart · New York.

  8. Aortic stenosis

    Science.gov (United States)

    ... but most often it develops later in life. Children with aortic stenosis may have other conditions present from birth. Aortic ... children may need aortic valve repair or replacement. Children with mild aortic stenosis may be able to take part in most ...

  9. Rod stiffness as a risk factor of proximal junctional kyphosis after adult spinal deformity surgery: comparative study between cobalt chrome multiple-rod constructs and titanium alloy two-rod constructs.

    Science.gov (United States)

    Han, Sanghyun; Hyun, Seung-Jae; Kim, Ki-Jeong; Jahng, Tae-Ahn; Lee, Subum; Rhim, Seung-Chul

    2017-07-01

    Little is known about the effect of rod stiffness as a risk factor of proximal junctional kyphosis (PJK) after adult spinal deformity (ASD) surgery. The aim of this study was to compare radiographic outcomes after the use of cobalt chrome multiple-rod constructs (CoCr MRCs) and titanium alloy two-rod constructs (Ti TRCs) for ASD surgery with a minimum 1-year follow-up. Retrospective case-control study in two institutes. We included 54 patients who underwent ASD surgery with fusion to the sacrum in two academic institutes between 2002 and 2015. Radiographic outcomes were measured on the standing lateral radiographs before surgery, 1 month postoperatively, and at ultimate follow-up. The outcome measures were composed of pre- and postoperative sagittal vertical axis (SVA), pre- and postoperative lumbar lordosis (LL), pre- and postoperative thoracic kyphosis (TK)+LL+pelvic incidence (PI), pre- and postoperative PI minus LL, level of uppermost instrumented vertebra (UIV), evaluation of fusion after surgery, the presence of PJK, and the occurrence of rod fracture. We reviewed the medical records of 54 patients who underwent ASD surgery. Of these, 20 patients had CoCr MRC and 34 patients had Ti TRC. Baseline data and radiographic measurements were compared between the two groups. The Mann-Whitney U test, the chi-square test, and the Fisher exact test were used to compare outcomes between the groups. The patients of the groups were similar in terms of age, gender, diagnosis, number of three-column osteotomy, levels fused, bone mineral density, preoperative TK, pre- and postoperative TK+LL+PI, SVA difference, LL change, pre- and postoperative PI minus LL, and location of UIV (upper or lower thoracic level). However, there were significant differences in the occurrence of PJK and rod breakage (PJK: CoCr MRC: 12 [60%] vs. Ti TRC: 9 [26.5%], p=.015; occurrence of rod breakage: CoCr MRC: 0 [0%] vs. Ti TRC: 11 [32.4%], p=.004). The time of PJK was less than 12 months after

  10. Traumatic Aortic Injury

    Directory of Open Access Journals (Sweden)

    Brianna Miner

    2016-09-01

    Full Text Available History of present illness: A 48-year-old male with unknown past medical history presents as a trauma after being hit by a car traveling approximately 25 miles per hour. On initial presentation, the patient is confused, combative, and not answering questions appropriately. The patient is hypotensive with a blood pressure of 68/40 and a heart rate of 50 beats per minute, with oxygen saturation at 96% on room air. FAST scan is positive for fluid in Morrison’s pouch, splenorenal space, and pericardial space. Significant findings: The initial chest x-ray showed an abnormal superior mediastinal contour (blue line, suggestive of a possible aortic injury. The CT angiogram showed extensive circumferential irregularity and outpouching of the distal aortic arch (red arrows compatible with aortic transection. In addition, there was a circumferential intramural hematoma, which extended through the descending aorta to the proximal infrarenal abdominal aorta (green arrow. There was also an extensive surrounding mediastinal hematoma extending around the descending aorta and supraaortic branches (purple arrows. Discussion: Traumatic aortic injury is a life-threatening event. The incidence of blunt thoracic aortic injury is low, between 1 to 2 percent of those patients with blunt thoracic trauma.1 However, approximately 80% of patients with traumatic aortic injury die at the scene.2 Therefore it is imperative to diagnose traumatic aortic injury in a timely fashion. The diagnosis can be difficult due to the non-specific signs and symptoms and other distracting injuries. Clinical suspicion should be based on the mechanism of the injury and the hemodynamic status of the patient. In any patient with blunt or penetrating trauma to the chest that is hemodynamically unstable, traumatic aortic injury should be on the differential. Chest x-ray can be used as a screening tool. A normal chest x-ray has a negative predictive value of approximately 97%. CTA chest is the

  11. Aneurisma de aorta abdominal justa-renal: correção endovascular combinada com derivação ilíaco-renal direita para criar colo proximal adequado Juxtarenal abdominal aortic aneurysm: combined endovascular and open repair with right iliorenal bypass to create adequate proximal neck

    Directory of Open Access Journals (Sweden)

    Matheus Bredarioli

    2007-06-01

    Full Text Available Homem de 78 anos de idade, portador de múltiplas morbidades clínicas deu entrada na emergência com um aneurisma de aorta abdominal justa-renal em condições hemodinâmicas estáveis. A tomografia computadorizada caracterizou aneurisma de 6 cm de diâmetro, e a distância do colo proximal do aneurisma era de 5 mm em relação à artéria renal direita e 28 mm à esquerda. Em virtude das condições clínicas do paciente, optou-se pelo reparo endovascular, mas previamente fez-se uma derivação ilíaco-renal direita com enxerto de politetrafluoretileno, via retroperitoneal para se criar um colo proximal adequado. Após quatro dias, o aneurisma de aorta abdominal foi corrigido colocando-se uma endoprótese Excluder® sem intercorrências. O seguimento pós-operatório evidenciou boa perfusão do rim esquerdo e ausência de migração ou endoleak da endoprótese. Este caso ilustra a combinação de técnicas para tornar possível o reparo de aneurisma de aorta abdominal justa-renal em pacientes de alto risco cirúrgico e anatomia desfavorável.A 78-year-old man with a juxtarenal abdominal aortic aneurysm and several comorbid conditions was admitted at the emergency room in hemodynamically stable conditions. Computed tomography revealed an aneurysm measuring 6 cm in diameter beginning 28 mm below the left renal artery and 5 mm below the right renal artery. Because of the patient's clinical status, a bypass from the right iliac artery to the right renal artery was performed through a retroperitoneal approach using a polytetrafluoroethylene vascular graft. Four days later, an endovascular aneurysm repair was successfully performed using an Excluder® stent-graft. Postoperative follow-up showed good left renal perfusion and no migration or endoleak. This case illustrates the effectiveness of combining open and endovascular techniques to repair juxtarenal abdominal aortic aneurysm in high-risk patients with unfavorable anatomy.

  12. Arterial stiffness and wave reflections in marathon runners.

    Science.gov (United States)

    Vlachopoulos, Charalambos; Kardara, Despina; Anastasakis, Aris; Baou, Katerina; Terentes-Printzios, Dimitrios; Tousoulis, Dimitris; Stefanadis, Christodoulos

    2010-09-01

    Regular aerobic exercise has beneficial effects on the cardiovascular system. Marathon running is an aerobic and extremely vigorous exercise. Arterial stiffness and wave reflections are independent predictors of cardiovascular risk. We investigated the acute effect of marathon race on aortic stiffness and wave reflections, as well as possible chronic alterations of these indexes in marathon runners. We studied 49 marathon runners (age 38 +/- 9 years) and 46 recreationally active control subjects (age 37 +/- 5 years). To investigate the acute effect of marathon race, a subgroup of 20 runners was evaluated after the race as well. Aortic stiffness was evaluated with carotid-femoral pulse wave velocity (PWV) and wave reflections with augmentation index (AIx). Marathon runners had significantly higher systolic, diastolic, pulse (both aortic and brachial), and mean pressures compared to controls (P Marathon runners had significantly higher PWV (6.89 m/s vs. 6.33 m/s, P Marathon race caused a significant fall in both AIx (12.2% vs. -5.8%, P marathon race, whereas aortic stiffness was not altered. Moreover, marathon runners have increased aortic stiffness and pressures, whereas wave reflections indexes do not differ compared to controls.

  13. Hemodynamic and Mechanical Properties of the Proximal Aorta in Young and Middle-Aged Adults With Isolated Systolic Hypertension: The Dallas Heart Study.

    Science.gov (United States)

    Yano, Yuichiro; Neeland, Ian J; Ayers, Colby; Peshock, Ronald; Berry, Jarett D; Lloyd-Jones, Donald M; Greenland, Philip; Mitchell, Gary F; Vongpatanasin, Wanpen

    2017-07-01

    The aim of this study was to assess characteristic impedance (Z c ) of the proximal aorta in young and middle-aged individuals with isolated systolic hypertension (ISH). Z c is an index of aortic stiffness relative to aortic size. In the Dallas Heart Study, 2001 untreated participants 18 to 64 years of age (mean age: 42.3 years; 44% black race) were divided into the following groups based on office blood pressure (BP) measurements: (1) optimal BP (systolic BP [SBP] hypertension (SBP hypertension (SBP ≥140 mm Hg and DBP ≥90 mm Hg; n=178). Z c , aortic arch pulse wave velocity, and minimum ascending aortic size were quantified using cardiovascular magnetic resonance. In multivariable-adjusted linear models, Z c was highest in the ISH group compared with the optimal BP, isolated diastolic hypertension, or systolic-diastolic hypertension groups (103.2±4.0 versus 68.3±2.1, 75.4±6.0, and 88.9±4.8 dyne*seconds/cm 5 , respectively; all P hypertension, or systolic-diastolic hypertension groups (6.3±0.3 versus 4.3±0.1, 4.4±0.4 and 5.5±0.3 m/s, respectively; all P 0.2). Results were similar in a subgroup of 1551 participants 18 to 49 years of age. In a multiracial population-based sample, we found evidence of a mismatch between proximal aortic stiffness and diameter in young and middle-aged adults with ISH. © 2017 American Heart Association, Inc.

  14. Carotid stiffness is associated with impairment of cognitive performance in individuals with and without type 2 diabetes. The Maastricht Study

    NARCIS (Netherlands)

    Geijselaers, Stefan L C; Sep, Simone J S; Schram, Miranda T.; van Boxtel, Martin P J; van Sloten, Thomas T.; Henry, Ronald M A; Reesink, Koen D.; Kroon, Abraham A.; Koster, Annemarie; Schaper, Nicolaas C.; Dagnelie, Pieter C.; van der Kallen, Carla J H; Biessels, Geert Jan; Stehouwer, Coen D A

    2016-01-01

    BACKGROUND AND AIMS: There is increasing evidence linking arterial (mainly aortic) stiffness and type 2 diabetes, a risk factor for arterial stiffness, to cognitive impairment and dementia. However, data on carotid stiffness, which may be especially relevant for cognitive performance, are scarce,

  15. Reoperative Aortic Root Replacement in Patients with Previous Aortic Root or Aortic Valve Procedures

    Directory of Open Access Journals (Sweden)

    Byung Kwon Chong

    2016-08-01

    Full Text Available Background: Generalization of standardized surgical techniques to treat aortic valve (AV and aortic root diseases has benefited large numbers of patients. As a consequence of the proliferation of patients receiving aortic root surgeries, surgeons are more frequently challenged by reoperative aortic root procedures. The aim of this study was to evaluate the outcomes of redo-aortic root replacement (ARR. Methods: We retrospectively reviewed 66 patients (36 male; mean age, 44.5±9.5 years who underwent redo-ARR following AV or aortic root procedures between April 1995 and June 2015. Results: Emergency surgeries comprised 43.9% (n=29. Indications for the redo-ARR were aneurysm (n=12, pseudoaneurysm (n=1, or dissection (n=6 of the residual native aortic sinus in 19 patients (28.8%, native AV dysfunction in 8 patients (12.1%, structural dysfunction of an implanted bioprosthetic AV in 19 patients (28.8%, and infection of previously replaced AV or proximal aortic grafts in 30 patients (45.5%. There were 3 early deaths (4.5%. During follow- up (median, 54.65 months; quartile 1–3, 17.93 to 95.71 months, there were 14 late deaths (21.2%, and 9 valve-related complications including reoperation of the aortic root in 1 patient, infective endocarditis in 3 patients, and hemorrhagic events in 5 patients. Overall survival and event-free survival rates at 5 years were 81.5%±5.1% and 76.4%±5.4%, respectively. Conclusion: Despite technical challenges and a high rate of emergency conditions in patients requiring redo-ARR, early and late outcomes were acceptable in these patients.

  16. Proximal Hypospadias

    Science.gov (United States)

    Kraft, Kate H.; Shukla, Aseem R.; Canning, Douglas A.

    2011-01-01

    Hypospadias results from abnormal development of the penis that leaves the urethral meatus proximal to its normal glanular position. Meatal position may be located anywhere along the penile shaft, but more severe forms of hypospadias may have a urethral meatus located at the scrotum or perineum. The spectrum of abnormalities may also include ventral curvature of the penis, a dorsally redundant prepuce, and atrophic corpus spongiosum. Due to the severity of these abnormalities, proximal hypospadias often requires more extensive reconstruction in order to achieve an anatomically and functionally successful result. We review the spectrum of proximal hypospadias etiology, presentation, correction, and possible associated complications. PMID:21516286

  17. Sweet potato (Ipomoea batatas) attenuates diet-induced aortic stiffening independent of changes in body composition

    National Research Council Canada - National Science Library

    Berrones, Adam J; Fleenor, Bradley S; Garner, Tyler; Campbell, Marilyn S; Ouyang, An; Du, Bing

    2017-01-01

    We hypothesized a sweet potato intervention would prevent high-fat (HF) diet−induced aortic stiffness, which would be associated with decreased arterial oxidative stress and increased mitochondrial uncoupling. Young (8-week old...

  18. Evaluation of arterial stiffness in nondiabetic chronic kidney disease patients

    Directory of Open Access Journals (Sweden)

    Bodanapu Mastanvalli

    2017-01-01

    Full Text Available Chronic kidney disease (CKD is a growing problem worldwide. Clinical and epidemiologic studies have shown that structural and functional changes that occur in major arteries are a major contributing factor to the high mortality in uremic patients. Recent studies have shown a stepwise increase of the carotid-femoral pulse wave velocity (cfPWV from CKD Stage 1 to Stage 5. We evaluated the cfPWV and augmentation index (AIx, as indirect markers of arterial stiffness in patients with nondiabetic CKD and compared the values with normal population; we also evaluated the relationship between various stages of CKD and arterial stiffness markers. This cross-sectional study was carried out in the Department of Nephrology for a duration of two years from January 15, 2012, to January 14, 2014. Fifty patients with nondiabetic CKD were studied along with 50 healthy volunteers who did not have CKD, who served as controls. Assessment of arterial stiffness (blood pressure, PWV, heart rate, aortic augmentation pressure, and AIx was performed using the PeriScope device. PWV positively correlated with systolic and diastolic blood pressure, mean aortic arterial pressure, serum creatinine, and serum uric acid and negatively correlated with estimated glomerular filtration rate. Arterial stiffness increased as CKD stage increased and was higher in nondiabetic CKD group than in the general population. Arterial stiffness progressed gradually from CKD Stage 2 to 5, and then abruptly, in dialysis patients. Measures to decrease the arterial stiffness and its influence on decreasing cardiovascular events need further evaluation.

  19. Aortic Valve Stenosis

    Science.gov (United States)

    ... rapid, fluttering heartbeat Not eating enough (mainly in children with aortic valve stenosis) Not gaining enough weight (mainly in children with aortic valve stenosis) The heart-weakening effects of aortic valve stenosis ...

  20. Bicuspid Aortic Valve

    Science.gov (United States)

    2006-08-01

    aortic valvular disease, endocarditis, ascending aortic aneurysm and aortic dissection.1-4 There is also an association of BAV with coarctation of...for aortic aneurysm , patients with BAV appear to have additional risks for aortic disease. Nistri et al.12 reported significant aortic root...Congenital heart disease in patients with Turner’s syndrome. Italian study group for Turner syndrome (ISGTS). J Pediatr 1998; 133:688-692. 7. Schmid

  1. Aortic stenosis: From diagnosis to optimal treatment

    Directory of Open Access Journals (Sweden)

    Tavčiovski Dragan

    2008-01-01

    Full Text Available Aortic stenosis is the most frequent valvular heart disease. Aortic sclerosis is the first characteristic lesion of the cusps, which is considered today as the process similar to atherosclerosis. Progression of the disease is an active process leading to forming of bone matrix and heavily calcified stiff cusps by inflammatory cells and osteopontin. It is a chronic, progressive disease which can remain asymptomatic for a long time even in the presence of severe aortic stenosis. Proper physical examination remains an essential diagnostic tool in aortic stenosis. Recognition of characteristic systolic murmur draws attention and guides further diagnosis in the right direction. Doppler echocardiography is an ideal tool to confirm diagnosis. It is well known that exercise tests help in stratification risk of asymptomatic aortic stenosis. Serial measurements of brain natriuretic peptide during a follow-up period may help to identify the optimal time for surgery. Heart catheterization is mostly restricted to preoperative evaluation of coronary arteries rather than to evaluation of the valve lesion itself. Currently, there is no ideal medical treatment for slowing down the disease progression. The first results about the effect of ACE inhibitors and statins in aortic sclerosis and stenosis are encouraging, but there is still not enough evidence. Onset symptoms based on current ACC/AHA/ESC recommendations are I class indication for aortic valve replacement. Aortic valve can be replaced with a biological or prosthetic valve. There is a possibility of percutaneous aortic valve implantation and transapical operation for patients that are contraindicated for standard cardiac surgery.

  2. Estimating Gear Teeth Stiffness

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2013-01-01

    The estimation of gear stiffness is important for determining the load distribution between the gear teeth when two sets of teeth are in contact. Two factors have a major influence on the stiffness; firstly the boundary condition through the gear rim size included in the stiffness calculation...... and secondly the size of the contact. In the FE calculation the true gear tooth root profile is applied. The meshing stiffness’s of gears are highly non-linear, it is however found that the stiffness of an individual tooth can be expressed in a linear form assuming that the contact length is constant....

  3. 'Stiff-person'-syndroom

    NARCIS (Netherlands)

    Vogels, R. L.; van Orshoven, N. P.; de Koning-Tijssen, M. A.; Wouda, E. J.

    2003-01-01

    In two patients, a man aged 54 years and a woman aged 49 years, stiff-person syndrome was diagnosed. This is a rare disorder of the central nervous system, with signs of an autoimmune pathogenesis. Patients present with pain and stiffness of the lower back, a complaint that is regularly seen in

  4. Aortic root surgery improves long-term survival after acute type A aortic dissection.

    Science.gov (United States)

    Hysi, Ilir; Juthier, Francis; Fabre, Olivier; Fouquet, Olivier; Rousse, Natacha; Banfi, Carlo; Pinçon, Claire; Prat, Alain; Vincentelli, André

    2015-04-01

    Our objective was to analyze the long term survival of patient operated on for acute type A aortic dissection. Between 1990 and 2010, 226 patients underwent emergency surgical operation for acute type A aortic dissection. We have followed the long-term outcomes. 144 patients were operated on with a supracommissural replacement of the ascending aorta (SCR) and 82 with an aortic root surgery (ARS, including 77 Bentall procedures and 5 Tirone David operations). Aortic cross-clamp was longer in ARS group (150.8 vs. 103.6 min, p<0.0001). Overall in-hospital mortality was lower in ARS group (20% vs. 34%, p 0.03). Median follow-up was 11.6 years. 10-year survival was higher in ARS group (85.7% vs. 65.9%, p 0.03) and 10-year freedom from aortic root reoperation was significantly lower in ARS group (93.4% vs. 82.9%, p 0.02). In a multivariate analysis aortic root surgery was an independent protective factor for proximal reoperations OR 0.393, CI 95% [0.206-0.748], p=0.005. Our study suggests that complete aortic root replacement in type A aortic dissection does not burden short-term outcomes, improves long-term survivals and decreases the rate of late reoperation. Whether this approach has to be preferred in younger patient has to be demonstrated in further studies. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  5. Aortic valve bypass

    DEFF Research Database (Denmark)

    Lund, Jens T; Jensen, Maiken Brit; Arendrup, Henrik

    2013-01-01

    In aortic valve bypass (AVB) a valve-containing conduit is connecting the apex of the left ventricle to the descending aorta. Candidates are patients with symptomatic aortic valve stenosis rejected for conventional aortic valve replacement (AVR) or transcatheter aortic valve implantation (TAVI...

  6. Advances in aortic disease management: a year in review.

    Science.gov (United States)

    Garg, Vinay; Ouzounian, Maral; Peterson, Mark D

    2016-03-01

    The medical and surgical management of aortic disease is continually changing in search for improved outcomes. Our objective is to highlight recent advances in a few select areas pertaining to aortic disease and aortic surgery: the genetics of aortopathy, medical therapy of aortic aneurysms, advances in cardiac imaging, and operative strategies for the aortic arch. As our understanding of the genetic basis for aortopathy continues to improve, routine genetic testing may be of value in assessing patients with genetically triggered forms of aortic disease. With regard to medical advances, treating patients with Marfan syndrome with either losartan or atenolol at an earlier stage in their disease course improves outcomes. In addition, novel imaging indices such as wall shear stress and aortic stiffness assessed by MRI may become useful markers of aortopathy and warrant further study. With regard to the optimal technique for cerebral perfusion in aortic arch surgery, high-quality data are still lacking. Finally, in patients with complex, multilevel aortic disease, the frozen elephant trunk is a viable single-stage option compared with the conventional elephant trunk, although with an increased risk for spinal cord injury. Based on recent advances, continued studies in genetics, cardiac imaging, and surgical trials will further elucidate the etiology of aortopathy and ultimately guide management, both medically and surgically.

  7. Vasopressor mechanisms in acute aortic coarctation hypertension

    Directory of Open Access Journals (Sweden)

    Salgado H.C.

    1997-01-01

    Full Text Available Angiotensin II (ANG II and vasopressin (AVP act together with the mechanical effect of aortic constriction in the onset of acute aortic coarctation hypertension. Blockade of ANG II and AVP V1 receptors demonstrated that ANG II acts on the prompt (5 min rise in pressure whereas AVP is responsible for the maintenance (30-45 min of the arterial pressure elevation during aortic coarctation. Hormone assays carried out on blood collected from conscious rats submitted to aortic constriction supported a role for ANG II in the early stage and a combined role for both ANG II and AVP in the maintenance of proximal hypertension. As expected, a role for catecholamines was ruled out in this model of hypertension, presumably due to the inhibitory effect of the sinoaortic baroreceptors. The lack of afferent feedback from the kidneys for AVP release from the central nervous system in rats with previous renal denervation allowed ANG II to play the major role in the onset of the hypertensive response. Median eminence-lesioned rats exhibited a prompt increase in proximal pressure followed by a progressive decline to lower hypertensive levels, revealing a significant role for the integrity of the neuroaxis in the maintenance of the aortic coarctation hypertension through the release of AVP. In conclusion, the important issue raised by this model of hypertension is the likelihood of a link between some vascular territory - probably renal - below the coarctation triggering the release of AVP, with this vasoconstrictor hormone participating with Ang II and the mechanical effect of aortic constriction in the acute aortic coarctation hypertension

  8. Effects of Ramadan fasting on body composition and arterial stiffness.

    Science.gov (United States)

    Sezen, Yusuf; Altiparmak, Ibrahim Halil; Erkus, Muslihittin Emre; Kocarslan, Aydemir; Kaya, Zekeriya; Gunebakmaz, Ozgur; Demirbag, Recep

    2016-12-01

    To examine the effects of Ramadan fasting on body composition, arterial stiffness and resting heart rate. This prospective study was conducted at the Department of Cardiology, Harran University, Sanliurfa, Turkey, during Ramadan 2015, and comprised overweight and obese males. Body composition, arterial stiffness and echocardiography were assessed before and after Ramadan. Body composition was assessed by bioelectrical impedance analysis using segmental body composition analyser. Arterial stiffness and haemodynamic parameters were also measured. SPSS 20 was used for data analysis. Of the 100 subjects enrolled, 70(70%) were included. The overall mean age was 37±7 years. No significant changes were observed in blood pressures, resting heart rate, aortic pulse wave velocity, aortic augmentation index-75, aortic pulse pressure, brachial pulse pressure, basal metabolic rate, total body water, fat-free mass, and echocardiographic parameters (p>0.05 each). Although aortic pulse wave velocity (m/s) and augmentation index-75 (%) decreased after fasting period compared to that of before Ramadan, these reductions did not reach statistically significant levels (8.6±1.8 vs. 8.9±1.9, and 13.6±6.6 vs. 14.7±9.3, respectively; p>0.05 each). Body mass index, waist-hip ratio, body water rate, percentage of body fat mass, body fat mass, and visceral fat mass percentage were significantly reduced (pRamadan. Ramadan fasting had beneficial effects on body composition, but did not have any significant effect on arterial stiffness and resting heart rate.

  9. Abdominal Aortic Dissection with Acute Mesenteric Ischemia in a Patient with Marfan Syndrome

    Directory of Open Access Journals (Sweden)

    Chii-Shyan Lay

    2006-07-01

    Full Text Available Marfan syndrome is an autosomal dominant inherited disorder of connective tissue, with various complications manifested primarily in the cardiovascular system. It potentially leads to aortic dissection and rupture, these being the major causes of death. We report a patient who complained of acute abdominal pain, which presented as acute mesenteric ischemia combined with abdominal aortic dissection. Echocardiography showed enlargement of the aortic root and mitral valve prolapse. Abdominal computed tomography scan revealed acute mesenteric ischemia due to abdominal aortic dissection. Finally, the patient underwent surgery of aortic root replacement and had a successful outcome. Therefore, we suggest that for optimal risk assessment and monitoring of patients with Marfan syndrome, both aortic stiffness and the diameter of the superior mesenteric vein compared with that of the superior mesenteric artery are useful screening methods to detect acute mesenteric ischemia secondary to abdominal aortic dissection. Early diagnosis and early treatment can decrease the high mortality rate of patients with Marfan syndrome.

  10. Large aortic aneurysm and dissection in a patient with Marfan's syndrome

    Directory of Open Access Journals (Sweden)

    Fernando Pivatto Júnior

    2015-04-01

    Full Text Available Marfan’s syndrome is an autosomal dominant disorder of connective tissue affecting approximately1 in5000 people. In individuals with this syndrome, more than 90% of deaths from known causes result from cardiovascular complications, such as aortic dissection, aortic regurgitation, and congestive cardiac failure. In this report, we present a patient with a large symptomatic aortic aneurysm and chronic dissection, severe aortic regurgitation and cardiomegaly, treated successfully with resection of the proximal aorta and placement of a mechanic aortic valved graft.

  11. Off-Pump Debranching and Thoracic Endovascular Aortic Repair for Aortic Arch Pathology.

    Science.gov (United States)

    Ghazy, Tamer; Mashhour, Ahmed; Schmidt, Torsten; Mahlmann, Adrian; Ouda, Ahmed; Florek, Hans-Joachim; Matschke, Klaus; Kappert, Utz

    2015-01-01

    This study aimed to simplify an until-now complex procedure for the treatment of proximal aortic arch pathology (zones 0 and 1), where a deep hypothermic circulatory arrest even with selective cerebral perfusion is still a high-risk procedure with accompanying splanchnic and spinal cord ischemia. From June 2012 until March 2013, 106 patients underwent aortic surgery in our institution, of whom, 20 patients underwent aortic arch surgery. Of the 20 patients, 7 with multiple comorbidities and a high operative risk and no other indication for a cardiopulmonary bypass were selected to undergo an off-pump aortic arch debranching and thoracic endovascular aortic repair: 4 patients had chronic dissections, and 3 patients had arch aneurysms. The procedure was performed through median sternotomy. The supraaortic branches were rerouted to the ascending aorta, and this process was followed by thoracic endovascular aortic repair of the aortic arch and proximal descending aorta. Transaortic antegrade stenting was performed in 5 cases. Cerebral protection and perfusion monitoring were achieved by biradial pressure monitoring, electroencephalogram, and online transcranial duplex sonography. The preoperative, operative, and postoperative data were collected and analyzed retrospectively. All procedures were successful. There were no conversions to cardiopulmonary bypass support. The mean operative time was 184 ± 24 minutes. Postoperatively, there was 1 rethoracotomy for bleeding and 1 cerebrovascular insult. The 30-day mortality was 1 patient. Off-pump aortic debranching with arch stenting is a reproducible procedure that could be favorable in certain situations, such as in patients with a higher operative risk profile, thereby reducing the risks associated with deep hypothermic circulatory arrest and also yielding favorable outcomes, even in an older patient cohort with more comorbidities.

  12. Effects of ventricular pacing-induced tachycardia on aortic mechanics in man.

    Science.gov (United States)

    Stefanadis, C; Dernellis, J; Vavuranakis, M; Tsiamis, E; Vlachopoulos, C; Toutouzas, K; Diamandopoulos, L; Pitsavos, C; Toutouzas, P

    1998-08-01

    Effects of pacing-induced tachycardia on left ventricular function have been studied extensively. However, little attention has been focused on aortic elastic properties during heart rate increments. The aim was to determine the effects of right ventricular pacing on the aortic elastic properties. We studied 14 normal subjects (baseline blood pressure, 129/84 +/- 10/6 mmHg; aortic diameter, 23.5/21.3 +/- 2.4/1.9 mm) at rest, during rapid right ventricular pacing (at five stepwise heart rate increases of 20 bpm every 2 min) and after 5 min recovery. Shifts as well as changes in the slope and the stiffness constant of the pressure diameter (p-d) relation, derived from simultaneous tip-micromanometer aortic pressure recordings and high-fidelity ultrasonic intravascular aortic diameter recordings, were used as indices of aortic stiffness. Wave reflection was also studied. Aortic pulse pressure and strain significantly decreased after pacing-induced tachycardia (p < 0.0001 and < 0.05, respectively). During pacing, the slope of the linear p-d relation as well as the stiffness constant were decreased, followed by increases at recovery (p < 0.0001). The augmentation index and the aortoventricular coupling ratio were significantly decreased (p < 0.0001). Pacing-induced increases in pulse frequency may result in improved aortic distensibility and aortoventricular coupling.

  13. Aortic Annular Enlargement during Aortic Valve Replacement

    OpenAIRE

    Selman Dumani; Ermal Likaj; Laureta Dibra; Stavri Llazo; Ali Refatllari

    2016-01-01

    In the surgery of aortic valve replacement is always attempted, as much as possible, to implant the larger prosthesis with the mains goals to enhance the potential benefits, to minimise transvalvular gradient, decrease left ventricular size and avoid the phenomenon of patient-prosthesis mismatch. Implantation of an ideal prosthesis often it is not possible, due to a small aortic annulus. A variety of aortic annulus enlargement techniques is reported to avoid patient-prosthesis mismatch. We pr...

  14. Aortic Annular Enlargement during Aortic Valve Replacement

    Directory of Open Access Journals (Sweden)

    Selman Dumani

    2016-09-01

    Full Text Available In the surgery of aortic valve replacement is always attempted, as much as possible, to implant the larger prosthesis with the mains goals to enhance the potential benefits, to minimise transvalvular gradient, decrease left ventricular size and avoid the phenomenon of patient-prosthesis mismatch. Implantation of an ideal prosthesis often it is not possible, due to a small aortic annulus. A variety of aortic annulus enlargement techniques is reported to avoid patient-prosthesis mismatch. We present the case that has submitted four three times open heart surgery. We used Manouguian technique to enlarge aortic anulus with excellent results during the fourth time of surgery.

  15. Aortic Annular Enlargement during Aortic Valve Replacement.

    Science.gov (United States)

    Dumani, Selman; Likaj, Ermal; Dibra, Laureta; Llazo, Stavri; Refatllari, Ali

    2016-09-15

    In the surgery of aortic valve replacement is always attempted, as much as possible, to implant the larger prosthesis with the mains goals to enhance the potential benefits, to minimise transvalvular gradient, decrease left ventricular size and avoid the phenomenon of patient-prosthesis mismatch. Implantation of an ideal prosthesis often it is not possible, due to a small aortic annulus. A variety of aortic annulus enlargement techniques is reported to avoid patient-prosthesis mismatch. We present the case that has submitted four three times open heart surgery. We used Manouguian technique to enlarge aortic anulus with excellent results during the fourth time of surgery.

  16. Aortic Aneurysm Statistics

    Science.gov (United States)

    ... connective tissue disorders, such as Marfan syndrome and Ehlers-Danlos syndrome, get thoracic aortic aneurysms. Signs and symptoms ... connective tissue disorders, such as Marfan syndrome and Ehlers-Danlos syndrome, can also increase your risk for aortic ...

  17. Suprasternal Aortic Valve Replacement: Key Technology and Techniques.

    Science.gov (United States)

    Kiser, Andy C; Caranasos, Thomas G; Peterson, Mark D; Buller, Christopher E; Borger, Michael A

    2017-10-01

    Suprasternal transcatheter aortic valve replacement offers patients, with unsuitable femoral artery anatomy, an alternative to transapical, direct aortic, and subclavian approaches. The Transit System (Aegis Surgical, Galway, Ireland) enables transcatheter aortic valve replacement directly into the ascending aorta or innominate artery through a small, suprasternal incision. The valve introducer sheath is inserted through a standard pursestring suture, which facilitates secure arterial closure. The proximity to the aortic valve promotes precise control. Proper patient selection and preoperative imaging is essential. A heart team working collaboratively in a hybrid operating room ensures procedural success. Using this approach, four different manufacturer's transcatheter valves have been used successfully. Suprasternal transcatheter aortic valve replacement is a safe and effective addition to the surgeon's armamentarium. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  18. Uric acid promotes vascular stiffness, maladaptive inflammatory responses and proteinuria in western diet fed mice.

    Science.gov (United States)

    Aroor, Annayya R; Jia, Guanghong; Habibi, Javad; Sun, Zhe; Ramirez-Perez, Francisco I; Brady, Barron; Chen, Dongqing; Martinez-Lemus, Luis A; Manrique, Camila; Nistala, Ravi; Whaley-Connell, Adam T; Demarco, Vincent G; Meininger, Gerald A; Sowers, James R

    2017-09-01

    Aortic vascular stiffness has been implicated in the development of cardiovascular disease (CVD) and chronic kidney disease (CKD) in obese individuals. However, the mechanism promoting these adverse effects are unclear. In this context, promotion of obesity through consumption of a western diet (WD) high in fat and fructose leads to excess circulating uric acid. There is accumulating data implicating elevated uric acid in the promotion of CVD and CKD. Accordingly, we hypothesized that xanthine oxidase(XO) inhibition with allopurinol would prevent a rise in vascular stiffness and proteinuria in a translationally relevant model of WD-induced obesity. Four-week-old C57BL6/J male mice were fed a WD with excess fat (46%) and fructose (17.5%) with or without allopurinol (125mg/L in drinking water) for 16weeks. Aortic endothelial and extracellular matrix/vascular smooth muscle stiffness was evaluated by atomic force microscopy. Aortic XO activity, 3-nitrotyrosine (3-NT) and aortic endothelial sodium channel (EnNaC) expression were evaluated along with aortic expression of inflammatory markers. In the kidney, expression of toll like receptor 4 (TLR4) and fibronectin were assessed along with evaluation of proteinuria. XO inhibition significantly attenuated WD-induced increases in plasma uric acid, vascular XO activity and oxidative stress, in concert with reductions in proteinuria. Further, XO inhibition prevented WD-induced increases in aortic EnNaC expression and associated endothelial and subendothelial stiffness. XO inhibition also reduced vascular pro-inflammatory and maladaptive immune responses induced by consumption of a WD. XO inhibition also decreased WD-induced increases in renal TLR4 and fibronectin that associated proteinuria. Consumption of a WD leads to elevations in plasma uric acid, increased vascular XO activity, oxidative stress, vascular stiffness, and proteinuria all of which are attenuated with allopurinol administration. Copyright © 2017 Elsevier Inc

  19. Arterial Stiffness and Pulse Wave Reflection in Young Adult Heterozygous Sickle Cell Carriers

    Directory of Open Access Journals (Sweden)

    Tünzale Bayramoğlu

    2013-12-01

    Full Text Available OBJECTIVE: Pulse wave velocity (PWV and aortic augmentation index (AI are indicators of arterial stiffness. Pulse wave reflection and arterial stiffness are related to cardiovascular events and sickle cell disease. However, the effect of these parameters on the heterozygous sickle cell trait (HbAS is unknown. The aim of this study is to evaluate the arterial stiffness and wave reflection in young adult heterozygous sickle cell carriers. METHODS: We enrolled 40 volunteers (20 HbAS cases, 20 hemoglobin AA [HbAA] cases aged between 18 and 40 years. AI and PWV values were measured by arteriography. RESULTS: Aortic blood pressure, aortic AI, and brachial AI values were significantly higher in HbAS cases compared to the control group (HbAA (p=0.033, 0.011, and 0.011, respectively. A statistically significant positive correlation was found between aortic pulse wave velocity and mean arterial pressure, age, aortic AI, brachial AI, weight, and low-density lipoprotein levels (p=0.000, 0.017, 0.000, 0.000, 0.034, and 0.05, respectively in the whole study population. Aortic AI and age were also significantly correlated (p=0.026. In addition, a positive correlation between aortic PWV and systolic blood pressure and a positive correlation between aortic AI and mean arterial pressure (p=0.027 and 0.009, respectively were found in HbAS individuals. Our study reveals that mean arterial pressure and heart rate are independent determinants for the aortic AI. Mean arterial pressure and age are independent determinants for aortic PWV. CONCLUSION: Arterial stiffness measurement is an easy, cheap, and reliable method in the early diagnosis of cardiovascular disease in heterozygous sickle cell carriers. These results may depend on the amount of hemoglobin S in red blood cells. Further studies are required to investigate the blood pressure changes and its effects on arterial stiffness in order to explain the vascular aging mechanism in the HbAS trait population.

  20. When operable patients become inoperable: conversion of a surgical aortic valve replacement into transcatheter aortic valve implantation

    DEFF Research Database (Denmark)

    Olsen, Lene Kjaer; Arendrup, Henrik; Engstrøm, Thomas

    2009-01-01

    Transcatheter aortic valve implantation (TAVI) is a relatively new treatment option for inoperable patients with severe aortic stenosis (AS). This case describes how a planned conventional surgical aortic valve replacement (AVR) on a 73-year-old woman was successfully converted to a TAVI procedure....... On extracorporal circulation it was reconized that the aortic annulus, the coronary ostiae and the proximal part of the ascending aorta were severely calcified making valve implantation impossible. Surgical closure without valve substitution was estimated to be associated with a high risk of mortality due......, and the prosthesis was sutured to the ascending aorta. With some manipulation of the prosthesis it was possible to suture the aorta circumferentially around the fully expanded upper part of the prosthesis. Post-procedurally the patient recovered successfully, with improved function capacity, aortic valve area...

  1. New type A dissection after acute type B aortic dissection.

    Science.gov (United States)

    Charlton-Ouw, Kristofer M; Sandhu, Harleen K; Leake, Samuel S; Miller, Charles C; Afifi, Rana O; Azizzadeh, Ali; Estrera, Anthony L; Safi, Hazim J

    2017-08-17

    Aortic dissection is a dynamic process that can progress both proximal and distal to the initial entry tear. We sought to determine associations for development of proximal progression or new type A aortic dissection (NTAD) after acute type B dissection (ATBD) and its effect on survival of the patient. We reviewed all cases of acute aortic dissection that we managed from 1999 to 2014. Univariate and bivariate analyses were performed to identify correlates of NTAD. Multivariable regression and proportional hazards regression analysis was done to determine the effect of dissection progression on long-term survival. Among 477 cases of ATBD managed, 19 (4.0%) patients developed NTAD during a median follow-up of 4.1 (interquartile range, 1.4-7.7) years. Median time from diagnosis of ATBD to NTAD was 124 (interquartile range, 23-1201) days. Baseline predictors for development of NTAD at initial ATBD admission included bicuspid aortic valve (P = .006) and age natural history of ATBD is such that there is a persistent risk of NTAD, with the highest risk in the first 6 months. Factors associated with NTAD include bicuspid aortic valve and young age. Thoracic endovascular aortic repair did not have a large effect on risk. Timely diagnosis and repair of NTAD are associated with good survival rates. Lifelong surveillance is warranted in all cases of descending thoracic aortic dissection regardless of initial treatment modality. Published by Elsevier Inc.

  2. Stiff quantum polymers

    OpenAIRE

    Kleinert, H.

    2009-01-01

    At ultralow temperatures, polymers exhibit quantum behavior, which is calculated here for the second and fourth moments of the end-to-end distribution in the large-stiffness regime. The result should be measurable for polymers in wide optical traps.

  3. Metabolomic profiles of lipid metabolism, arterial stiffness and hemodynamics in male coronary artery disease patients

    Directory of Open Access Journals (Sweden)

    Kaido Paapstel

    2016-06-01

    Conclusions: We demonstrated an independent association between the serum medium- and long-chain acylcarnitine profile and aortic stiffness for the CAD patients. In addition to the lipid-related classical CVD risk markers, the intermediates of lipid metabolism may serve as novel indicators for altered vascular function.

  4. Qualitative haemodynamic validation of a percutaneous temporary aortic valve: a proof of concept study.

    Science.gov (United States)

    Ho, P C

    2011-02-01

    The concept of temporary aortic valves has been suggested in the clinical settings of acute aortic regurgitation and transcatheter aortic valve replacement procedure (TAVR). In TAVR, suggestions have been made to pre-treat or remove the diseased aortic valve prior to implantation of the replacement valve. A successful temporary aortic valve must demonstrate the ability to prevent life-threatening haemodynamics of massive aortic regurgitation. A novel temporary aortic valve (TAV) design, comprised of inflatable balloon elements as a check-valve, can readily be deployed and retrieved via a catheter-system. A simple flow model is set up to test the TAV's performance in severe aortic regurgitation. With induced aortic regurgitation, placement of the TAV is found to increase the distal aortic diastolic pressure, to reduce the widened pulse pressure, to protect proximal aorta-left ventricle from diastolic pressure elevation and to reduce the aortic regurgitant volume. In conclusion, continued development of the TAV system can lead to a successful temporary aortic valve to be used in various appropriate clinical settings.

  5. Robust segmentation methods with an application to aortic pulse wave velocity calculation.

    Science.gov (United States)

    Babin, Danilo; Devos, Daniel; Pižurica, Aleksandra; Westenberg, Jos; Vansteenkiste, Ewout; Philips, Wilfried

    2014-04-01

    Aortic stiffness has proven to be an important diagnostic and prognostic factor of many cardiovascular diseases, as well as an estimate of overall cardiovascular health. Pulse wave velocity (PWV) represents a good measure of the aortic stiffness, while the aortic distensibility is used as an aortic elasticity index. Obtaining the PWV and the aortic distensibility from magnetic resonance imaging (MRI) data requires diverse segmentation tasks, namely the extraction of the aortic center line and the segmentation of aortic regions, combined with signal processing methods for the analysis of the pulse wave. In our study non-contrasted MRI images of abdomen were used in healthy volunteers (22 data sets) for the sake of non-invasive analysis and contrasted magnetic resonance (MR) images were used for the aortic examination of Marfan syndrome patients (8 data sets). In this research we present a novel robust segmentation technique for the PWV and aortic distensibility calculation as a complete image processing toolbox. We introduce a novel graph-based method for the centerline extraction of a thoraco-abdominal aorta for the length calculation from 3-D MRI data, robust to artifacts and noise. Moreover, we design a new projection-based segmentation method for transverse aortic region delineation in cardiac magnetic resonance (CMR) images which is robust to high presence of artifacts. Finally, we propose a novel method for analysis of velocity curves in order to obtain pulse wave propagation times. In order to validate the proposed method we compare the obtained results with manually determined aortic centerlines and a region segmentation by an expert, while the results of the PWV measurement were compared to a validated software (LUMC, Leiden, the Netherlands). The obtained results show high correctness and effectiveness of our method for the aortic PWV and distensibility calculation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. On gear tooth stiffness evaluation

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard; Jørgensen, Martin Felix

    2014-01-01

    The estimation of gear stiffness is important for determining the load distribution between the gear teeth when two sets of teeth are in contact. Two factors have a major influence on the stiffness; firstly the boundary condition through the gear rim size included in the stiffness calculation...

  7. Elasticity of Stiff Biopolymers

    OpenAIRE

    Ghosh, Abhijit; Samuel, Joseph; Sinha, Supurna

    2007-01-01

    We present a statistical mechanical study of stiff polymers, motivated by experiments on actin filaments and the considerable current interest in polymer networks. We obtain simple, approximate analytical forms for the force-extension relations and compare these with numerical treatments. We note the important role of boundary conditions in determining force-extension relations. The theoretical predictions presented here can be tested against single molecule experiments on neurofilaments and ...

  8. Arterial stiffness, atherosclerosis and cardiovascular risk: Pathophysiologic mechanisms and emerging clinical indications.

    Science.gov (United States)

    Palombo, Carlo; Kozakova, Michaela

    2016-02-01

    Arterial stiffness results from a degenerative process affecting mainly the extracellular matrix of elastic arteries under the effect of aging and risk factors. Changes in extracellular matrix proteins and in the mechanical properties of the vessel wall related to arterial stiffening may activate number of mechanisms involved also in the process of atherosclerosis. Several noninvasive methods are now available to estimate large artery stiffness in the clinical setting, including carotid-femoral pulse wave velocity, the reference for aortic stiffness estimate, and local distensibility measures of superficial arteries, namely carotid and femoral. An independent predictive value of arterial stiffness for cardiovascular events has been demonstrated in general as well as in selected populations, and reference values adjusted for age and blood pressure have been established. Thus, arterial stiffness is emerging as an interesting tissue biomarker for cardiovascular risk stratification and estimation of the individual "biological age". This paper overviews the mechanisms accounting for development and progression of arterial stiffness and for associations between arterial stiffness, atherosclerotic burden and incident cardiovascular events, summarizes the evidence and caveat for clinical use of stiffness as surrogate marker of cardiovascular risk, and briefly outlines some emerging methods for large artery stiffness characterization. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Proximal renal tubular acidosis

    Science.gov (United States)

    Renal tubular acidosis - proximal; Type II RTA; RTA - proximal; Renal tubular acidosis type II ... by alkaline substances, mainly bicarbonate. Proximal renal tubular acidosis (Type II RTA) occurs when bicarbonate is not ...

  10. Endovascular Aortic Aneurysm Repair with Chimney and Snorkel Grafts: Indications, Techniques and Results

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Rakesh P., E-mail: rpatel9@nhs.net [Northwick Park Hospital, Department of Vascular Radiology (United Kingdom); Katsargyris, Athanasios, E-mail: kthanassos@yahoo.com; Verhoeven, Eric L. G., E-mail: Eric.Verhoeven@klinikum-nuernberg.de [Klinikum Nuernberg, Department of Vascular and Endovascular Surgery (Germany); Adam, Donald J., E-mail: donald.adam@tiscali.co.uk [Heartlands Hospital, Department of Vascular Surgery (United Kingdom); Hardman, John A., E-mail: johnhardman@doctors.org.uk [Royal United Hospital Bath, Department of Vascular Radiology (United Kingdom)

    2013-12-15

    The chimney technique in endovascular aortic aneurysm repair (Ch-EVAR) involves placement of a stent or stent-graft parallel to the main aortic stent-graft to extend the proximal or distal sealing zone while maintaining side branch patency. Ch-EVAR can facilitate endovascular repair of juxtarenal and aortic arch pathology using available standard aortic stent-grafts, therefore, eliminating the manufacturing delays required for customised fenestrated and branched stent-grafts. Several case series have demonstrated the feasibility of Ch-EVAR both in acute and elective cases with good early results. This review discusses indications, technique, and the current available clinical data on Ch-EVAR.

  11. The cardiovascular effects of aortic clamping and unclamping

    African Journals Online (AJOL)

    presence of overt coronary artery disease. 2. The radius of the ventricle influences wall tension. In other words .... follows acute aortic constriction. This recovery of end-diastolic volume and pressure toward control .... concomitant valvular disease is beyond the scope of this manuscript. The circulation proximal to the clamp.

  12. Stiffness, resilience, compressibility

    Energy Technology Data Exchange (ETDEWEB)

    Leu, Bogdan M. [Argonne National Laboratory, Advanced Photon Source (United States); Sage, J. Timothy, E-mail: jtsage@neu.edu [Northeastern University, Department of Physics and Center for Interdisciplinary Research on Complex Systems (United States)

    2016-12-15

    The flexibility of a protein is an important component of its functionality. We use nuclear resonance vibrational spectroscopy (NRVS) to quantify the flexibility of the heme iron environment in the electron-carrying protein cytochrome c by measuring the stiffness and the resilience. These quantities are sensitive to structural differences between the active sites of different proteins, as illustrated by a comparative analysis with myoglobin. The elasticity of the entire protein, on the other hand, can be probed quantitatively from NRVS and high energy-resolution inelastic X-ray scattering (IXS) measurements, an approach that we used to extract the bulk modulus of cytochrome c.

  13. Debranching Solutions in Endografting for Complex Thoracic Aortic Dissections

    Energy Technology Data Exchange (ETDEWEB)

    Goksel, Onur Selcuk, E-mail: onurgokseljet@gmail.com [Istanbul University, Istanbul Medical Faculty, Cardiovascular Surgery, Istanbul (Turkey); Guven, Koray [Istanbul University, Istanbul Medical Faculty, Radiology, Istanbul (Turkey); Karatepe, Celalettin [Mustafa Kemal Medical Faculty, Cardiovascular Surgery, Istanbul (Turkey); Gok, Emre [Istanbul University, Istanbul Medical Faculty, Cardiovascular Surgery, Istanbul (Turkey); Acunas, Bulent [Istanbul University, Istanbul Medical Faculty, Radiology, Istanbul (Turkey); Cinar, Bayer [Medical Park Hospital, Istanbul (Turkey); Alpagut, Ufuk [Istanbul University, Istanbul Medical Faculty, Cardiovascular Surgery, Istanbul (Turkey)

    2014-08-15

    Conventional surgical repair of thoracic aortic dissections is a challenge due to mortality and morbidity risks. We analyzed our experience in hybrid aortic arch repair for complex dissections of the aortic arch. Between 2009 and 2013, 18 patients (the mean age of 67 ± 8 years-old) underwent hybrid aortic arch repair. The procedural strategy was determined on the individual patient. Thirteen patients had type I repair using trifurcation and another patient with bifurcation graft. Two patients had type II repair with replacement of the ascending aorta. Two patients received extra-anatomic bypass grafting to left carotid artery allowing covering of zone 1. Stent graft deployment rate was 100%. No patients experienced stroke. One patient with total debranching of the aortic arch following an acute dissection of the proximal arch expired 3 months after TEVAR due to heart failure. There were no early to midterm endoleaks. The median follow-up was 20 ± 8 months with patency rate of 100%. Various debranching solutions for different complex scenarios of the aortic arch serve as less invasive procedures than conventional open surgery enabling safe and effective treatment of this highly selected subgroup of patients with complex aortic pathologies.

  14. Genetic variation in the fibrinogen-alpha and fibrinogen-gamma genes in relation to arterial stiffness: the Rotterdam Study.

    Science.gov (United States)

    Sie, Mark P S; Isaacs, Aaron; de Maat, Moniek P M; Mattace-Raso, Francesco U S; Uitterlinden, André G; Kardys, Isabella; Hofman, Albert; Hoeks, Arnold P G; Reneman, Robert S; van Duijn, Cornelia M; Witteman, Jaqueline C M

    2009-07-01

    Arterial stiffness increases with age and predicts cardiovascular disease. Fibrinogen is an acute-phase protein and some studies showed an association with arterial stiffness. We studied genetic variation in the fibrinogen-alpha (FGA) and fibrinogen-gamma (FGG) genes, by means of single nucleotide polymorphisms (FGA: -58 G/A, 1374 G/A, 1526 T/C, 312 Thr/Ala, and FGG: 4288 G/A, 6326 G/A, 7792 T/C) and resultant haplotypes in relation to arterial stiffness. The present study (n = 3891) was embedded in the Rotterdam Study. Associations of the fibrinogen level, genotypes and haplotypes with aortic stiffness (pulse wave velocity), carotid stiffness (distensibility coefficient) and pulse pressure were investigated in men and women by analyses of variance, linear regression and by haplotype analyses. Analyses were adjusted for age, mean arterial pressure, heart rate, known cardiovascular risk factors and atherosclerosis. Genotype analyses yielded associations of FGA-58 G/A (P = 0.040, for trend) and FGA-1526 T/C (P = 0.004, for trend) with the fibrinogen levels, but no consistent associations with arterial stiffness, in women. FGA-haplotype 4 was associated with the fibrinogen level (P = 0.02) in women. FGA-haplotype 3 and FGG-haplotype 2 were associated with aortic stiffness (P = 0.05) in women. No associations were found in men. Findings indicate that the fibrinogen level and genetic variation in the FGA and FGG genes may influence arterial stiffness in women.

  15. Pharmacological modulation of arterial stiffness.

    LENUS (Irish Health Repository)

    Boutouyrie, Pierre

    2011-09-10

    Arterial stiffness has emerged as an important marker of cardiovascular risk in various populations and reflects the cumulative effect of cardiovascular risk factors on large arteries, which in turn is modulated by genetic background. Arterial stiffness is determined by the composition of the arterial wall and the arrangement of these components, and can be studied in humans non-invasively. Age and distending pressure are two major factors influencing large artery stiffness. Change in arterial stiffness with drugs is an important endpoint in clinical trials, although evidence for arterial stiffness as a therapeutic target still needs to be confirmed. Drugs that independently affect arterial stiffness include antihypertensive drugs, mostly blockers of the renin-angiotensin-aldosterone system, hormone replacement therapy and some antidiabetic drugs such as glitazones. While the quest continues for \\'de-stiffening drugs\\

  16. Death from ascending aortic aneurysm secondary to quadricuspid aortic valve.

    Science.gov (United States)

    Massoni, Francesco; Ricci, Serafino

    2014-12-01

    Quadricuspid aortic valve is a very rare cardiac malformation (<1.46%) that is very rarely associated with other diseases, such as ascending aortic aneurysm.The authors present a case of cardiac tamponade from a rupture of the ascending aortic aneurysm that may have been caused, as shown by a review of the literature, by the quadricuspid aortic valve.

  17. Women with abdominal aortic aneurysms have more extensive aortic neck pathology.

    Science.gov (United States)

    Hultgren, Rebecka; Vishnevskaya, Liya; Wahlgren, Carl Magnus

    2013-07-01

    The proportion of women with abdominal aortic aneurysm (AAA) treated with endovascular aortic repair (EVAR) is lower than for open repair (OR). Unfavorable morphologic features for EVAR in women with AAA may explain this disproportion. The objective of this study was to identify morphologic features in AAA patients undergoing elective repair with special emphasis on gender differences. Patients undergoing elective repair from January 1, 2006 to December 31, 2008 at our university's vascular unit were included in this study. Computed tomography (CT) angiograms were analyzed. Morphologic features considered unfavorable for EVAR rather than open repair (OR) included: infrarenal aortic neck 60°; circumferential neck thrombus; neck width >32 mm; iliac arteries more of the other aortic neck exclusion criteria. One hundred seventy-two patients, including 140 men and 32 women, were treated during the study period, which included 99 with OR (21 women, 78 men) and 73 with EVAR (11 women, 62 men). Morphologic unsuitability for EVAR was 44% (75 of 172) and was not statistically different between women and men [47% (15 of 32) vs. 43% (60 of 140), P = 0.70]. Aortic neck pathology was the dominating feature for unsuitability for EVAR (69 of 75, 92%), and 85 of 172 patients had an unsuitable aortic neck. This rate was not different between women and men [19 of 32 (59%) vs. 66 of 140 (47%), P = 0.24]. Iliac unsuitability rates were 11% (19 of 172) and were not different between women and men [4 of 32 (12%) vs. 15 of 140 (11%), P = 0.76]. In patients unsuitable for EVAR, the proximal aortic necks showed more extensive aortic neck pathology in women than in men [8 of 15 (53%) vs. 13 of 60 (22%), P = 0.02]. More men had only short neck pathology [22 of 60 (37%) vs. 1 of 15 (7%), P = 0.03]. Aortic neck pathology is the dominating cause of EVAR exclusion in both genders. A higher proportion of women have more pathologic neck anatomy. Future development of EVAR devices should focus on

  18. Dynamic stiffness of suction caissons

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Liingaard, Morten; Andersen, Lars

    The purpose of this report is to evaluate the dynamic soil-structure interaction of suction caissons for offshore wind turbines. The investigation is limited to a determination of the vertical dynamic stiffness of suction caissons. The soil surrounding the foundation is homogenous with linear...... viscoelastic properties. The dynamic stiffness of the suction caisson is expressed by dimensionless frequency-dependent dynamic stiffness coefficients corresponding to the vertical degree of freedom. The dynamic stiffness coefficients for the foundations are evaluated by means of a dynamic three...

  19. Trabecular meshwork stiffness in glaucoma.

    Science.gov (United States)

    Wang, Ke; Read, A Thomas; Sulchek, Todd; Ethier, C Ross

    2017-05-01

    Alterations in stiffness of the trabecular meshwork (TM) may play an important role in primary open-angle glaucoma (POAG), the second leading cause of blindness. Specifically, certain data suggest an association between elevated intraocular pressure (IOP) and increased TM stiffness; however, the underlying link between TM stiffness and IOP remains unclear and requires further study. We here first review the literature on TM stiffness measurements, encompassing various species and based on a number of measurement techniques, including direct approaches such as atomic force microscopy (AFM) and uniaxial tension tests, and indirect methods based on a beam deflection model. We also briefly review the effects of several factors that affect TM stiffness, including lysophospholipids, rho-kinase inhibitors, cytoskeletal disrupting agents, dexamethasone (DEX), transforming growth factor-β2 (TGF-β2), nitric oxide (NO) and cellular senescence. We then describe a method we have developed for determining TM stiffness measurement in mice using a cryosection/AFM-based approach, and present preliminary data on TM stiffness in C57BL/6J and CBA/J mouse strains. Finally, we investigate the relationship between TM stiffness and outflow facility between these two strains. The method we have developed shows promise for further direct measurements of mouse TM stiffness, which may be of value in understanding mechanistic relations between outflow facility and TM biomechanical properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Relative latency of responses of chemoreceptor afferents from aortic and carotid bodies.

    Science.gov (United States)

    Lahiri, S; Nishino, T; Mulligan, E; Mokashi, A

    1980-02-01

    Discharges from aortic and carotid body chemoreceptor afferents were simultaneously recorded in 18 anesthetized cats to test the hypothesis that aortic chemoreceptors, because of their proximity to the heart, respond to changes in arterial blood gases before carotid chemoreceptors. We found that carotid chemoreceptor responses to the onset of hypoxia and hypercapnia, and to the intravenously administered excitatory drugs (cyanide, nicotine, and doxapram), preceded those of aortic chemoreceptors. Postulating that this unexpected result was due to differences in microcirculation and mass transport, we also investigated their relative speed of responses to changes in arterial blood pressure. The aortic chemoreceptors responded to decreases in arterial blood pressure before the carotid chemoreceptors, supporting the idea that the aortic body has microcirculatory impediments not generally present in the carotid body. These findings strengthened the concept that carotid bodies are more suited for monitoring blood gas changes due to respiration, whereas aortic bodies are for monitoring circulation.

  1. Evaluation of myocardial strain and artery elasticity using speckle tracking echocardiography and high-resolution ultrasound in patients with bicuspid aortic valve.

    Science.gov (United States)

    Li, Yang; Deng, You-Bin; Bi, Xiao-Jun; Liu, Ya-Ni; Zhang, Jun; Li, Li

    2016-07-01

    Reduced artery elasticity and reduced myocardial strain were present in patients with bicuspid aortic valve (BAV). Their relation to dilation of proximal aorta is unclear. We aimed to study their relation to dilation of proximal aorta. We studied 57 BAV patients categorized into 2 subgroup according to proximal ascending aortic dimensions (nondilated elasticity and myocardial strain in BAV patients, supporting the need for detailed and extensive vascular and cardiac surveillance in BAV patients.

  2. Uncomplicated obesity is associated with abnormal aortic function assessed by cardiovascular magnetic resonance

    Directory of Open Access Journals (Sweden)

    Channon Keith M

    2008-02-01

    Full Text Available Abstract Aims Obese subjects with insulin resistance and hypertension have abnormal aortic elastic function, which may predispose them to the development of left ventricular dysfunction. We hypothesised that obesity, uncomplicated by other cardiovascular risk factors, is independently associated with aortic function. Methods and results We used magnetic resonance imaging to measure aortic compliance, distensibility and stiffness index in 27 obese subjects (BMI 33 kg/m2 without insulin resistance and with normal cholesterol and blood pressure, and 12 controls (BMI 23 kg/m2. Obesity was associated with reduced aortic compliance (0.9 ± 0.1 vs. 1.5 ± 0.2 mm2/mmHg in controls, p -1 × 10-3, p Conclusion Aortic elastic function is abnormal in obese subjects without other cardiovascular risk factors. These findings highlight the independent importance of obesity in the development of cardiovascular disease.

  3. Amiloride Improves Endothelial Function and Reduces Vascular Stiffness in Female Mice Fed a Western Diet

    Directory of Open Access Journals (Sweden)

    Luis A. Martinez-Lemus

    2017-06-01

    Full Text Available Obese premenopausal women lose their sex related cardiovascular disease protection and develop greater arterial stiffening than age matched men. In female mice, we have shown that consumption of a Western diet (WD, high in fat and refined sugars, is associated with endothelial dysfunction and vascular stiffening, which occur via activation of mineralocorticoid receptors and associated increases in epithelial Na+ channel (ENaC activity on endothelial cells (EnNaC. Herein our aim was to determine the effect that reducing EnNaC activity with a very-low-dose of amiloride would have on decreasing endothelial and arterial stiffness in young female mice consuming a WD. To this end, we fed female mice either a WD or control diet and treated them with or without a very-low-dose of the ENaC-inhibitor amiloride (1 mg/kg/day in the drinking water for 20 weeks beginning at 4 weeks of age. Mice consuming a WD were heavier and had greater percent body fat, proteinuria, and aortic stiffness as assessed by pulse-wave velocity than those fed control diet. Treatment with amiloride did not affect body weight, body composition, blood pressure, urinary sodium excretion, or insulin sensitivity, but significantly reduced the development of endothelial and aortic stiffness, aortic fibrosis, aortic oxidative stress, and mesenteric resistance artery EnNaC abundance and proteinuria in WD-fed mice. Amiloride also improved endothelial-dependent vasodilatory responses in the resistance arteries of WD-fed mice. These results indicate that a very-low-dose of amiloride, not affecting blood pressure, is sufficient to improve endothelial function and reduce aortic stiffness in female mice fed a WD, and suggest that EnNaC-inhibition may be sufficient to ameliorate the pathological vascular stiffening effects of WD-induced obesity in females.

  4. Limit cycles and stiffness control with variable stiffness actuators

    NARCIS (Netherlands)

    Carloni, Raffaella; Marconi, Lorenzo

    2012-01-01

    Variable stiffness actuators realize highly dynamic systems, whose inherent mechanical compliance can be properly exploited to obtain a robust and energy-efficient behavior. The paper presents a control strategy for variable stiffness actuators with the primarily goal of tracking a limit cycle

  5. Fenestrated endografts for complex abdominal aortic aneurysms.

    Science.gov (United States)

    Mastracci, Tara M

    2010-12-01

    The treatment of aortic aneurysm disease using endovascular stent grafts has evolved over the past 20 years. Extending this approach to aneurysms involving the visceral aorta has required development of fenestrated endografts. By creating branches to accommodate visceral vessels, the proximal landing zone can be chosen based on the adequacy of the aortic wall, rather than the constraints of visceral vessels. This allows for a more stable repair, and permits a minimally invasive approach in even very complex aneurysms. As the technology becomes more widespread, the use of these grafts has emerged from an experimental form to standard of care in some jurisdictions. Thus, many patients who might have previously been considered high risk for aneurysm repair are now candidates for surgery. This article outlines the basic concepts behind the development of fenestrated endografts, their current use, and the future of the technology.

  6. An analysis of variables affecting aortic neck length with implications for fenestrated endovascular repair of abdominal aortic aneurysm.

    Science.gov (United States)

    Stark, Madeline; Suresh, Adithya; Alexander, Jason; Cragg, Andrew

    2014-05-01

    A major factor in the selection of patients for endovascular aneurysm repair (EVAR) is the character of the aortic neck, and studies suggest that many patients are treated outside of the instructions for use (IFU) criteria. By analyzing aortic neck morphology, we hope to identify factors that may influence decision making about the use of fenestrated endografts as an alternative to extending the neck limitations of traditional endografts. A retrospective analysis was completed on 111 patients who underwent computed tomography angiography (CTA) scans between May 1, 2009 and January 3, 2011 for the evaluation of abdominal aortic aneurysm (AAA). Individual characteristics of neck and aneurysm morphology were analyzed to establish whether certain factors determined suitability for EVAR with traditional nonfenestrated endografts. In considering augmented neck lengths (ANL), anatomic measurements of distance from the start of aortic dilatation to the lowest renal artery (LRA) and highest renal artery (HRA) were analyzed. Measurements were analyzed using Stata software (version 11.2; StataCorp, College Station, TX). There were 86 men and 25 women in the patient population, with an average age of 72.9 years. In 46 patients, the proximal neck length was relationship between AAA maximum diameter and proximal neck length (rs = -0.2237; P = 0.018), indicating that as aneurysm size increases, proximal neck length decreases. There was a significant correlation between proximal neck length and proximal neck diameter (rs = -0.2585; P = 0.006) and between proximal neck length and angle (rs = -0.2355; P = 0.013), and between proximal neck diameter and right iliac maximum diameter (rs = 0.2329; P = 0.014). Using fenestration to place an endograft above the LRA would create an ANL of >15 mm in 20 of 40 patients with aortic necks deemed too short to be eligible for EVAR using conventional infrarenal graft positioning. Extending the graft above the HRA would create an ANL of >15 mm in

  7. The posttraumatic stiff elbow.

    Science.gov (United States)

    Morrey, Bernard F

    2005-02-01

    The development of joint contracture is a well-recognized complication of elbow injury. Precise causes of the propensity of this joint for ankylosis are understood poorly. Yet, treatment is emerging and therefore the indications and willingness on the part of the surgeon to address this problem is improving. Limited open procedures have emerged during the past several years that are safe and effective by improving arcs of motion of 50-70 degrees in approximately 80-90% of patients. For severe injuries that involve the articular surface, interposition arthroplasty is less documented but has been shown to be effective but constitutes one of the most challenging technical procedures. Joint replacement arthroplasty generally should not be considered as a treatment for posttraumatic stiffness unless the patient is older than 65 years. The experience with this procedure indicates that with linked semiconstrained implants, approximately 80% of patients will achieve a near functional arc of motion. Arthroscopic intervention shows the greatest activity of investigation and clinical expansion. The learning curve is defined by a concern of complications to the neural structures and the fear of this complication has limited the application but the emerging documentation of the safeness of this option also has been associated with improved effectiveness. Therefore, arthroscopic intervention for the stiff elbow, particularly those with soft tissue extrinsic involvement, is emerging as the treatment of choice in many instances. The investigation regarding the medical treatment of altering the tendency of the soft tissue to go through such intense contracture is in its infancy but suggests that this could be a long-term solution at least for many patients.

  8. Core curriculum case illustration: cardiac tamponade complicating proximal aortic dissection.

    Science.gov (United States)

    Aaltonen, H Laura; Linnau, Ken F; Fadl, Shaimaa Abdelhassib

    2017-06-14

    This is the 39th installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at http://www.erad.org/page/CCIP_TOC .

  9. Thrombosed abdominal aortic aneurysm associated with an extensively "shaggy" aorta repaired anatomically via a thoracoabdominal approach with supraceliac aortic clamping: report of a case.

    Science.gov (United States)

    Tanaka, Satofumi; Tanaka, Kuniyoshi; Morioka, Koichi; Yamada, Narihisa; Takamori, Atsushi; Handa, Mitsuteru; Ihaya, Akio; Sasaki, Masato; Ikeda, Takeshi

    2010-09-01

    A 76-year-old man with a history of multiple laparotomies and severe coronary artery disease was referred to our hospital after the sudden development of pain and numbness in the lower extremities. Computed tomography showed a thrombosed abdominal aortic aneurysm and diffuse aortic atherosclerosis; compatible with a "shaggy aorta." A good response to thrombolytic therapy permitted elective scheduling of abdominal aortic surgery after coronary artery bypass grafting. We operated via an extended left retroperitoneal approach through a thoracoabdominal incision. Epiaortic ultrasonography revealed that only the supraceliac aorta was free of mobile thrombi and had minimal plaque; we therefore placed a proximal aortic cross-clamp there. Anatomic aortic reconstruction was then performed successfully using an aorto-biiliac graft to restore adequate distal blood flow. There were no vital-organ ischemic complications, and the postoperative course was satisfactory.

  10. Mapping the longitudinal wall stiffness heterogeneities within intact canine aortas using Pulse Wave Imaging (PWI) ex vivo.

    Science.gov (United States)

    Shahmirzadi, Danial; Narayanan, Prathyush; Li, Ronny X; Qaqish, William W; Konofagou, Elisa E

    2013-07-26

    The aortic stiffness has been found to be a useful independent indicator of several cardiovascular diseases such as hypertension and aneurysms. Existing methods to estimate the aortic stiffness are either invasive, e.g. catheterization, or yield average global measurements which could be inaccurate, e.g., tonometry. Alternatively, the aortic pulse wave velocity (PWV) has been shown to be a reliable marker for estimating the wall stiffness based on the Moens-Korteweg (M-K) formulation. Pulse Wave Imaging (PWI) is a relatively new, ultrasound-based imaging method for noninvasive and regional estimation of PWV. The present study aims at showing the application of PWI in obtaining localized wall mechanical properties by making PWV measurements on several adjacent locations along the ascending thoracic to the suprarenal abdominal aortic trunk in its intact vessel form. The PWV estimates were used to calculate the regional wall modulus based on the M-K relationship and were compared against conventional mechanical testing. The findings indicated that for the anisotropic aortic wall, the PWI estimates of the modulus are smaller than the circumferential modulus by an average of -32.22% and larger than the longitudinal modulus by an average of 25.83%. Ongoing work is focused on the in vivo applications of PWI in normal and pathological aortas with future implications in the clinical applications of the technique. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Outcome of plate osteosynthesis in the management of proximal ...

    African Journals Online (AJOL)

    Background: This paper reports the aetiology, presentation and management of proximal humeral fractures (PHF) in our setup. Objective: To ... Five of thirty two operated cases (15%) developed significant shoulder joint stiffness. ... There is need for arthroplasty in those with severe injury, particularly those with osteoporosis.

  12. [Established Indications for Invasive Treatment of Thoracic Aortic Aneurysm].

    Science.gov (United States)

    Akin, Ibrahim; Nienaber, Christoph

    2015-11-01

    Thoracic aortic aneurysms are associated with high morbidity and mortality due to rupture and dissection. Conservative medical treatment is associated with a 5-year survival rate of 13 %. This rises to 70-79 % in case of surgical treatment. While classical surgical strategies still dominate the care for acute and chronic pathology of the ascending aorta and the proximal arch region, new endovascular concepts are emerging and are likely to evolve as primary treatment strategies for descending aortic pathology in suitable patients. © Georg Thieme Verlag KG Stuttgart · New York.

  13. Aneurysm growth after late conversion of thoracic endovascular aortic repair

    Directory of Open Access Journals (Sweden)

    Hirofumi Kasahara

    2015-01-01

    Full Text Available A 69-year-old man underwent thoracic endovascular aortic repair of a descending aortic aneurysm. Three years later, he developed impending rupture due to aneurysmal expansion that included the proximal landing zone. Urgent open surgery was performed via lateral thoracotomy, and a Dacron graft was sewn to the previous stent graft distally with Teflon felt reinforcement. Postoperatively, four sequential computed tomography scans demonstrated that the aneurysm was additionally increasing in size probably due to continuous hematoma production, suggesting a possibility of endoleaks. This case demonstrates the importance of careful radiologic surveillance after endovascular repair, and also after partial open conversion.

  14. Arterial stiffness and cognitive impairment.

    Science.gov (United States)

    Li, Xiaoxuan; Lyu, Peiyuan; Ren, Yanyan; An, Jin; Dong, Yanhong

    2017-09-15

    Arterial stiffness is one of the earliest indicators of changes in vascular wall structure and function and may be assessed using various indicators, such as pulse-wave velocity (PWV), the cardio-ankle vascular index (CAVI), the ankle-brachial index (ABI), pulse pressure (PP), the augmentation index (AI), flow-mediated dilation (FMD), carotid intima media thickness (IMT) and arterial stiffness index-β. Arterial stiffness is generally considered an independent predictor of cardiovascular and cerebrovascular diseases. To date, a significant number of studies have focused on the relationship between arterial stiffness and cognitive impairment. To investigate the relationships between specific arterial stiffness parameters and cognitive impairment, elucidate the pathophysiological mechanisms underlying the relationship between arterial stiffness and cognitive impairment and determine how to interfere with arterial stiffness to prevent cognitive impairment, we searched PUBMED for studies regarding the relationship between arterial stiffness and cognitive impairment that were published from 2000 to 2017. We used the following key words in our search: "arterial stiffness and cognitive impairment" and "arterial stiffness and cognitive impairment mechanism". Studies involving human subjects older than 30years were included in the review, while irrelevant studies (i.e., studies involving subjects with comorbid kidney disease, diabetes and cardiac disease) were excluded from the review. We determined that arterial stiffness severity was positively correlated with cognitive impairment. Of the markers used to assess arterial stiffness, a higher PWV, CAVI, AI, IMT and index-β and a lower ABI and FMD were related to cognitive impairment. However, the relationship between PP and cognitive impairment remained controversial. The potential mechanisms linking arterial stiffness and cognitive impairment may be associated with arterial pulsatility, as greater arterial pulsatility

  15. Emergency endovascular repair of acute descending thoracic aortic dissection

    Directory of Open Access Journals (Sweden)

    Muhammad Anees Sharif

    2007-11-01

    Full Text Available Muhammad Anees Sharif, Mark Edward O’Donnell, Paul Henry Blair, Peter KennedyDepartment of Vascular and Endovascular Surgery, Royal Victoria Hospital, Grosvenor Road, Belfast, BT12 6BA, United KingdomBackground: Acute descending thoracic aortic dissection is a life-threatening emergency. It is not often considered as the initial diagnosis in patients presenting with epigastric pain and could easily be missed in a busy casualty department.Aim: This case report is aimed to highlight the feasibility of the technique and the need for long-term surveillance following endovascular repair of acute thoracic aortic dissection.Results: The patient presented with epigastric pain radiating to the interscapular region with a stable hemodynamic status. A computerized tomography (CT scan demonstrated type B thoracic aortic dissection of the proximal descending thoracic aorta. A successful endovascular repair was carried out with uneventful recovery and follow-up CT scan six years after stent-grafting shows satisfactory position of the stent-graft, patent false lumen in the abdominal aorta perfusing the right kidney, and progressively enlarging diameter of the abdominal aorta.Conclusion: Thoracic aortic dissection should be considered as a differential diagnosis in patients presenting with epigastric and interscapular chest pain. Emergency endovascular repair of acute thoracic aortic dissection is feasible and relatively safe. Regular follow-up with CT scan is required to evaluate the long-term effi cacy and identify the need for re-intervention.Keywords: aortic, dissection, endovascular, thoracic

  16. Stiffness of desiccating insect wings

    Energy Technology Data Exchange (ETDEWEB)

    Mengesha, T E; Vallance, R R [Department of Mechanical Engineering, The George Washington University, 738 Phillips Hall, 801 22nd St NW, Washington, DC 20052 (United States); Mittal, R, E-mail: vallance@gwu.edu [Department of Mechanical Engineering, Johns Hopkins University, 126 Latrobe Hall, 3400 N Charles Street, Baltimore, MD 21218 (United States)

    2011-03-15

    The stiffness of insect wings is typically determined through experimental measurements. Such experiments are performed on wings removed from insects. However, the wings are subject to desiccation which typically leads to an increase in their stiffness. Although this effect of desiccation is well known, a comprehensive study of the rate of change in stiffness of desiccating insect wings would be a significant aid in planning experiments as well as interpreting data from such experiments. This communication presents a comprehensive experimental analysis of the change in mass and stiffness of gradually desiccating forewings of Painted Lady butterflies (Vanessa cardui). Mass and stiffness of the forewings of five butterflies were simultaneously measured every 10 min over a 24 h period. The averaged results show that wing mass declined exponentially by 21.1% over this time period with a time constant of 9.8 h, while wing stiffness increased linearly by 46.2% at a rate of 23.4 {mu}N mm{sup -1} h{sup -1}. For the forewings of a single butterfly, the experiment was performed over a period of 1 week, and the results show that wing mass declined exponentially by 52.2% with a time constant of 30.2 h until it reached a steady-state level of 2.00 mg, while wing stiffness increased exponentially by 90.7% until it reached a steady-state level of 1.70 mN mm{sup -1}. (communication)

  17. Brief Report: Physical Activity, Body Mass Index and Arterial Stiffness in Children with Autism Spectrum Disorder: Preliminary Findings.

    Science.gov (United States)

    Heffernan, Kevin S; Columna, Luis; Russo, Natalie; Myers, Beth A; Ashby, Christine E; Norris, Michael L; Barreira, Tiago V

    2018-02-01

    We examined the association between physical activity (PA), body mass index (BMI) and novel measures of subclinical cardiovascular disease (CVD) in 15 children with autism spectrum disorder (ASD) (mean age 7 ± 2 years, 2 girls). PA was objectively assessed using accelerometry as time spent in moderate-vigorous physical activity (MVPA). Arterial stiffness was measured via aortic pulse wave velocity (PWV) and taken as a marker of subclinical CVD risk. MVPA was inversely associated with aortic PWV (r = - 0.46, p < 0.05). BMI percentile was positively associated with aortic PWV (r = 0.61, p < 0.05). Overall findings suggest that reduced PA and higher body mass in children with ASD are associated with increased arterial stiffness which may have a detrimental impact on overall cardiovascular health.

  18. Type A aortic dissection: Are there CT signs suggestive of valvular involvement?

    Energy Technology Data Exchange (ETDEWEB)

    Platon, Alexandra, E-mail: alexandra.platon@hcuge.ch [Department of Radiology, Emergency Radiology Unit, University Hospital of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211, Geneva (Switzerland); Bernard, Stephane; Perrin, Nils [Department of Radiology, Emergency Radiology Unit, University Hospital of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211, Geneva (Switzerland); Murith, Nicolas [Division of Cardiovascular Surgery, University Hospital of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211, Geneva (Switzerland); John, Gregor [Department of Internal medicine/Geriatrics and Rehabilitation, University Hospital of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211, Geneva (Switzerland); Department of Internal Medicine, Hôpital neuchâtelois, 2300 La Chaux-de-Fonds (Switzerland); Perneger, Thomas [Division of Clinical Epidemiology, University Hospital of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211, Geneva (Switzerland); Rutschmann, Olivier T. [Division of Emergency Medicine, University Hospitals of Geneva and School of Medicine, 4 rue Gabrielle-Perret-Gentil, 1211, Geneva (Switzerland); Poletti, Pierre-Alexandre [Department of Radiology, Emergency Radiology Unit, University Hospital of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211, Geneva (Switzerland)

    2016-11-15

    Highlights: • Non-ECG gated CT rarely shows valve involvement in type A aortic dissection. • Diameters of the aortic root in type A aortic dissection were measured on initial CT. • Sinus of Valsalva diameter >45 mm is 100% specific to predict aortic valve involvement. - Abstract: Aim: To identify the predictive signs of aortic valve involvement on the non-electrocardiogram (ECG)-gated admission computed tomography (CT) of patients with Type A aortic dissection (AD) according to the Stanford classification. Materials and methods: We retrospectively analyzed the non-ECG-gated CT examinations of patients admitted to the emergency department who underwent surgery for Type A AD over a period of 4 years. The diameter of the following structures was calculated as the mean of the smallest and largest diameters (mm) measured in two different planes: aortic annulus, sinus of Valsalva, sinotubular junction, and proximal ascending aorta. These parameters were compared against operative reports in order to determine whether they were predictive of aortic valve involvement. Results: In total, 20 patients (13 men and 7 women) of a mean age of 59.5 years (29–80) were included, 55% of patients (11/20) having surgically proven valvular involvement. The mean diameters (in mm) of the aortic annulus, sinus of Valsalva, sinotubular junction and proximal ascending aorta in the group with (and without, respectively) valvular involvement was 27.7 (26.7), 44.3 (38.1), 42.6 (36.6), and 47.8 (45.9). Only the measurement of the mean diameter of the sinuses of Valsalva was significantly predictive (p = 0.02) of aortic valve involvement. Conclusion: Our findings suggest that measuring the diameter of the sinuses of Valsalva on non-ECG-gated admission CT examinations allows for predicting aortic valve involvement in Type A AD patients.

  19. Aortic bypass and bilateral renal autotransplantation for mid-aortic syndrome.

    Science.gov (United States)

    Poupalou, Anna; Salomon, Rémi; Boudjemline, Younes; Allain-Launay, Emma; Aigrain, Yves; Chardot, Christophe

    2013-09-01

    Middle aortic syndrome (MAS) is a rare condition characterized by stenosis of the proximal abdominal aorta and the origin of the renal and digestive arteries. When medical therapy and interventional radiology fail to control threatening reno-vascular arterial hypertension (AHT), surgery is required and may need several interventions, which are usually delayed until late childhood. We report on a 3-year-old girl with severe AHT (180/130 mmHg) caused by MAS. There was no evidence of generalized vascular disease or complications of AHT. AHT failed to respond to medical therapy (five drugs), endovascular dilatation, and stenting was considered unfeasible due to the complex multiple strictures. Surgery consisted of: explantation of the two kidneys; aortic bypass between the lower thoracic and lower abdominal aorta using a prosthetic graft; reimplantation of the kidneys onto the normal iliac arteries. The post-operative course was uneventful. Owing to recurrent stenosis of the re-implanted renal arteries, endoluminal dilatations were performed 4 and 5 months after surgery. Two years after surgery, the child is alive and well, off anti-hypertensive therapy, with normal blood pressure. Mild aortic syndrome can be treated with a one-stage surgical repair with aorto-aortic bypass and bilateral auto-transplantation, even in young children.

  20. Surgical treatment of pararenal aortic aneurysms in the elderly.

    Science.gov (United States)

    Illuminati, G; D'Urso, A; Ceccanei, G; Caliò, F; Vietri, F

    2007-12-01

    Until fenestrated endografts will become the standard treatment of pararenal aortic aneurysms, open surgical repair will currently be employed for the repair of this condition. Suprarenal aortic control and larger surgical dissection represent additional technical requirements for the treatment of pararenal aneurysms compared to those of open infrarenal aortic aneurysms, which may be followed by an increased operative mortality and morbidity rate. As this may be especially true when dealing with pararenal aneurysms in an elderly patients' population, we decided to retrospectively review our results of open pararenal aortic aneurysm repair in elderly patients, in order to compare them with those reported in the literature. Twenty-one patients over 75 years of age were operated on for pararenal aortic aneurysms in a ten-year period. Exposure of the aorta was obtained by means of a retroperitoneal access, through a left flank incision on the eleventh rib. When dealing with interrenal aortic aneurysm the left renal artery was revascularized with a retrograde bypass arising from the aortic graft, proximally bevelled on the ostium of the right renal artery. Two patients died of acute intestinal ischemia, yielding a postoperative mortality of 9.5%. Nonfatal complications included 2 pleural effusions, a transitory rise in postoperative serum creatinine levels in 3 cases, and one retroperitoneal hematoma. Mean renal ischemia time was 23 min, whereas mean visceral ischemia time was 19 min. Mean inhospital stay was 11 days. Pararenal aortic aneurysms in the elderly can be surgically repaired with results that are similar to those obtained in younger patients.

  1. Multiset proximity spaces

    Directory of Open Access Journals (Sweden)

    A. Kandil

    2016-10-01

    Full Text Available A multiset is a collection of objects in which repetition of elements is essential. This paper is an attempt to explore the theoretical aspects of multiset by extending the notions of compact, proximity relation and proximal neighborhood to the multiset context. Examples of new multiset topologies, open multiset cover, compact multiset and many identities involving the concept of multiset have been introduced. Further, an integral examples of multiset proximity relations are obtained. A multiset topology induced by a multiset proximity relation on a multiset M has been presented. Also the concept of multiset δ- neighborhood in the multiset proximity space which furnishes an alternative approach to the study of multiset proximity spaces has been mentioned. Finally, some results on this new approach have been obtained and one of the most important results is: every T4- multiset space is semi-compatible with multiset proximity relation δ on M (Theorem 5.10.

  2. What factors accelerate aortic stiffening in hemodialysis patients? An observational study.

    Science.gov (United States)

    Matsumae, Tomoji; Ueda, Kazuo; Abe, Yasuhiro; Nishimura, Shinsuke; Murakami, Genji; Saito, Takao

    2010-03-01

    Increased aortic stiffness is an independent predictor of death from cardiovascular disease in patients with end-stage renal disease (ESRD). Various factors that contribute to carotid-femoral pulse wave velocity (cfPWV) as a surrogate of aortic stiffness have been identified, but determinants of long-term worsening of aortic stiffness remain to be elucidated. To clarify the factors that accelerate aortic stiffness in hemodialysis patients, 148 patients with ESRD on hemodialysis were evaluated. At baseline, cfPWV and ankle-brachial blood pressure index (ABPI) were measured and clinical status including biochemical parameters, with or without hepatitis c virus (HCV) infection, diabetes mellitus (DM), cardiovascular disease, cerebrovascular disease and peripheral arterial disease at baseline, were evaluated. The cfPWV was measured again after a 3-year follow up and the annual change in cfPWV was calculated. The cfPWV decreased in 54 patients, worsened slowly in 47 (annual change in cfPWV ranged from 0 to 0.33 ms(-1) per year), and worsened rapidly in 47 patients (annual change in cfPWV was more than 0.33 ms(-1) per year). The prevalences of DM, HCV infection and peripheral arterial disease were the highest in the rapid progression group. Univariate analysis showed that age, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), LDL-C/HDL-C ratio, HCV infection, ABPI and number of vasculopathies were significantly associated with annual change in cfPWV. Stepwise regression analysis identified ABPI, LDL-C/HDL-C ratio and HCV infection as independent determinants of worsening of cfPWV. Further studies are needed to investigate the mechanism of HCV-related enhancement of aortic stiffness in ESRD patients.

  3. Aortic Diameter Growth in Children With a Bicuspid Aortic Valve

    NARCIS (Netherlands)

    Merkx, R.; Duijnhouwer, A.L.; Vink, E. de; Roos-Hesselink, J.W.; Schokking, M.

    2017-01-01

    Knowledge of aortic growth in patients with bicuspid aortic valve (BAV) is essential to identify patients at risk for dissection, but data on children remain unclear. We retrospectively evaluated the aortic diameters of all pediatric BAV patients, identified through an echocardiographic database

  4. Aortic Diameter Growth in Children With a Bicuspid Aortic Valve

    NARCIS (Netherlands)

    Merkx, R. (Remy); A.L. Duijnhouwer (Anthonie L.); Vink, E. (Evelien); J.W. Roos-Hesselink (Jolien); M. Schokking (Michiel)

    2017-01-01

    textabstractKnowledge of aortic growth in patients with bicuspid aortic valve (BAV) is essential to identify patients at risk for dissection, but data on children remain unclear. We retrospectively evaluated the aortic diameters of all pediatric BAV patients, identified through an echocardiographic

  5. Aortic intimal separation resulting from manual cardiopulmonary resuscitation-completing the spectrum of blunt thoracic aortic injury complicating CPR.

    Science.gov (United States)

    Williams, Andrew S; Castonguay, Mathieu; Murray, Shawn K

    2016-11-01

    Blunt thoracic aortic injury (BTAI) resulting from cardiopulmonary resuscitation (CPR) is rarely reported and most reports are of aortic rupture. Clinical reports have also documented aortic dissection and intramural hematomas with sequential imaging showing the development of these aortic injuries after the administration of CPR, suggesting that non-transmural aortic injury may also result from CPR. We report partial separation of an aortic intimal atheromatous plaque as a component injury in a case with multiple complications of manual CPR. A 74-year-old male presented to the emergency room (ER) with a 2-day history of chest pain. While in the ER, he suffered witnessed cardiac arrest and resuscitative attempts were pursued for 60 min prior to declaring death. At autopsy, there were numerous injuries attributable to CPR, including bilateral rib fractures, sternal fracture, retrosternal and mediastinal hemorrhage, epicardial ecchymoses, and ruptured pericardium. There was a perforated inferior wall myocardial infarct with a large left hemothorax. There was partial separation/laceration of an intimal atheromatous plaque on the anterior wall of the ascending aorta proximal to the origin of the brachiocephalic artery, forming a triangular flap, without associated intramedial dissection or hematoma. There was no thrombus formation, effectively excluding existence of the laceration prior to circulatory arrest. This aortic injury provides pathologic confirmation of non-transmural BTAI definitively sustained during manual CPR. Pathologists and clinicians alike should be cognizant of the possibility of BTAI resulting from CPR, which may manifest the full range of severity from intimal tear through aortic rupture.

  6. Measurement of the Aortic Diameter in the Asymptomatic Thai Population in Siriraj Hospital: Assessment with Multidetector CT

    Directory of Open Access Journals (Sweden)

    Krisdee Prabhasavat

    2016-07-01

    Full Text Available Objective: The purpose of this study was to determine normal reference values of intra-thoracic and abdominal aortic diameters of asymptomatic Thai adults obtained by multidetector computed tomography. Secondary end points were evaluation of relationships between aortic diameters and patients’ demographic data or potential risk factors of cardiovascular disease. Methods: Three hundred and ten Thai adults in Siriraj Hospital who had no any signs or symptoms of cardio- vascular disease that examined with computed tomography (CT of chest and whole abdomen were investigated in this study. Aortic diameters were measured at eight predefined intra-thoracic and abdominal levels on CT images, including ascending aorta, proximal transverse aortic arch, distal transverse aortic arch, aortic isthmus, thoracoabdominal junction, celiac axis, suprarenal aorta and aortic bifurcation. Analysis of data was performed with regard to patients’ demographic data (age, sex, weight, and height and three potential risk factors of cardio- vascular disease (hypertension, dyslipidemia and diabetes mellitus. Furthermore, we also recorded the co-morbid non-cardiovascular underlying diseases which were classified into seven groups, including tumors (malignant and benign tumors, infectious diseases, inflammatory diseases, autoimmune diseases, degenerative diseases, psychiatric diseases and others. Results: Aortic diameters were 3.14±0.40 cm. at the ascending aorta, 2.88 ± 0.34 cm. at proximal transverse aortic arch, 2.65±0.30 cm. at distal transverse aortic arch, 2.46 ± 0.31cm. at aortic isthmus, 2.10± 0.27 cm. at thoracoab- dominal junction, 1.99 ± 0.26 cm. at celiac axis, 1.81 ±0.25 cm. at suprarenal aorta, and 1.47±0.21 cm. at aortic bifurcation. Overall aortic diameters tend to continuously significantly decrease aortic diameters from proximal to distal direction from ascending aorta to aortic bifurcation. Men had slightly more enlarged aortic diameters in all

  7. Morning blood pressure surge and arterial stiffness in newly diagnosed hypertensive patients.

    Science.gov (United States)

    Kıvrak, Ali; Özbiçer, Süleyman; Kalkan, Gülhan Yüksel; Gür, Mustafa

    2017-06-01

    We aimed to investigate the relationship between the morning blood pressure (BP) surge and arterial stiffness in patients with newly diagnosed hypertension. Three hundred and twenty four (mean age 51.7 ± 11.4 years) patients who had newly diagnosed hypertension with 24 h ambulatory BP monitoring were enrolled. Parameters of arterial stiffness, pulse wave velocity and augmentation index (Aix) were measured by applanation tonometry and aortic distensibility was calculated by echocardiography. Compared with the other groups, pulse wave velocity, day-night systolic BP (SBP) difference (p surge high group. Aortic distensibility values were significantly lower in morning BP surge high group compared to the other groups (p surge was found to be independently associated with pulse wave velocity (β = 0.286, p surge and arterial stiffness which is a surrogate endpoint for cardiovascular diseases. The inverse relationship between morning BP surge and aortic distensibility and direct relation found in our study is new to the literature.

  8. Pathogenetic Basis of Aortopathy and Aortic Valve Disease

    Science.gov (United States)

    2018-02-19

    Aortopathies; Thoracic Aortic Aneurysm; Aortic Valve Disease; Thoracic Aortic Disease; Thoracic Aortic Dissection; Thoracic Aortic Rupture; Ascending Aortic Disease; Descending Aortic Disease; Ascending Aortic Aneurysm; Descending Aortic Aneurysm; Marfan Syndrome; Loeys-Dietz Syndrome; Ehlers-Danlos Syndrome; Shprintzen-Goldberg Syndrome; Turner Syndrome; PHACE Syndrome; Autosomal Recessive Cutis Laxa; Congenital Contractural Arachnodactyly; Arterial Tortuosity Syndrome

  9. Coronary ostial involvement in acute aortic dissection: detection with 64-slice cardiac CT.

    LENUS (Irish Health Repository)

    Ryan, E Ronan

    2012-02-01

    A 41-year-old man collapsed after lifting weights at a gym. Following admission to the emergency department, a 64-slice cardiac computed tomography (CT) revealed a Stanford Type A aortic dissection arising from a previous coarctation repair. Multiphasic reconstructions demonstrated an unstable, highly mobile aortic dissection flap that extended proximally to involve the right coronary artery ostium. Our case is an example of the application of electrocardiogram-gated cardiac CT in directly visualizing involvement of the coronary ostia in acute aortic dissection, which may influence surgical management.

  10. Double Invasive Blood Pressure Monitoring for Cesarean Delivery in a Pregnant Woman With Aortic Coarctation.

    Science.gov (United States)

    Barcellos, Bruno Mendonça; Loureiro, Fernanda Martins; Sampaio, Livia Fernandes; de Resende, Marco Antonio Cardoso

    2016-08-01

    Aortic coarctation is a discrete narrowing of the proximal thoracic aorta. It is poorly tolerated during pregnancy because of its association with hypertension, cerebrovascular accident, and aortic rupture. We report a case of severe uncorrected congenital aortic coarctation in a 31-year-old symptomatic pregnant woman at 29 weeks of gestation who underwent successful cesarean delivery with an epidural anesthetic technique. Transthoracic echocardiography showed a gradient of 75 mm Hg. To avoid undiagnosed arterial hypotension and inadequate uteroplacental flow distal to the coarctation, double (radial and femoral) invasive arterial blood pressure measurement was used to monitor both pre- and postcoarctation arterial blood pressure.

  11. Biomaterial stiffness determines stem cell fate.

    Science.gov (United States)

    Lv, Hongwei; Wang, Heping; Zhang, Zhijun; Yang, Wang; Liu, Wenbin; Li, Yulin; Li, Lisha

    2017-06-01

    Stem cells have potential to develop into numerous cell types, thus they are good cell source for tissue engineering. As an external physical signal, material stiffness is capable of regulating stem cell fate. Biomaterial stiffness is an important parameter in tissue engineering. We summarize main measurements of material stiffness under different condition, then list and compare three main methods of controlling stiffness (material amount, crosslinking density and photopolymeriztion time) which interplay with one another and correlate with stiffness positively, and current advances in effects of biomaterial stiffness on stem cell fate. We discuss the unsolved problems and future directions of biomaterial stiffness in tissue engineering. Copyright © 2017. Published by Elsevier Inc.

  12. Recurrent Aortic Dissection: Observations From the International Registry of Aortic Dissection.

    Science.gov (United States)

    Isselbacher, Eric M; Bonaca, Marc P; Di Eusanio, Marco; Froehlich, James; Bassone, Eduardo; Sechtem, Udo; Pyeritz, Reed; Patel, Himanshu; Khoynezhad, Ali; Eckstein, Hans-Henning; Jondeau, Guillaume; Ramponi, Fabio; Abbasi, Mohammad; Montgomery, Daniel; Nienaber, Christoph A; Eagle, Kim; Lindsay, Mark E

    2016-10-04

    Improved medical care after initial aortic dissection (AD) has led to increased survivorship and a population of individuals at risk for further cardiovascular events, including recurrent AD. Reports describing recurrent ADs have been restricted to small numbers of patients from single institutions. We used the IRAD (International Registry of Acute Aortic Dissection) database to examine the clinical profiles and outcomes of patients with recurrent AD. We identified 204 patients enrolled in IRAD with recurrent AD. For the primary analysis, patient characteristics, interventions, and outcomes were analyzed and compared with 3624 patients with initial AD. Iterative logistic modeling was performed to investigate variables associated with recurrent AD. Cox regression analyses were used to determine variables associated with 5-year survival. A subset of recurrent AD patients was analyzed for anatomic and demographic details of initial and recurrent ADs. Patients with recurrent AD were more likely to have Marfan syndrome (21.5% versus 3.1%; P<0.001) but not bicuspid aortic valve (3.6% versus 3.2%; P=0.77). Descending aortic dimensions were greater in patients with recurrent AD than in patients with initial AD independently of sentinel dissection type (type A: 4.3 cm [3.5-5.6 cm] versus 3.3 cm [2.9-3.7 cm], P<0.001; type B: 5.0 cm [3.9-6.0 cm] versus 4.0 cm [3.5-4.8 cm], P<0.001), and this observation was accentuated among patients with Marfan syndrome. In multivariate analysis, the diagnosis of Marfan syndrome independently predicted recurrent AD (hazard ratio, 8.6; 95% confidence interval, 5.8-12.8; P<0.001). Patients with recurrent AD who presented with proximal followed by distal AD were younger than patients who experienced distal followed by proximal dissection AD (42.1±16.1 versus 54.3±14.8 years; P=0.004). Among those suffering acute aortic dissection, 5% have a history of a prior aortic dissection. Recurrent AD is strongly associated with Marfan syndrome.

  13. Early Results of Chimney Technique for Type B Aortic Dissections Extending to the Aortic Arch

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Chen [Affiliated Hospital of Nantong University, Department of General Surgery (China); Tang, Hanfei; Qiao, Tong; Liu, Changjian; Zhou, Min, E-mail: 813477618@qq.com [The Affiliated Hospital of Nanjing University Medical School, Department of Vascular Surgery, Nanjing Drum Tower Hospital (China)

    2016-01-15

    ObjectiveTo summarize our early experience gained from the chimney technique for type B aortic dissection (TBAD) extending to the aortic arch and to evaluate the aortic remodeling in the follow-up period.MethodsFrom September 2011 to July 2014, 27 consecutive TBAD patients without adequate proximal landing zones were retrograde analyzed. Chimney stent-grafts were deployed parallel to the main endografts to reserve flow to branch vessels while extending the landing zones. In the follow-up period, aortic remodeling was observed with computed tomography angiography.ResultsThe technical success rate was 100 %, and endografts were deployed in zone 0 (n = 3, 11.1 %), zone 1 (n = 18, 66.7 %), and zone 2 (n = 6, 22.2 %). Immediately, proximal endoleaks were detected in 5 patients (18.5 %). During a mean follow-up period of 17.6 months, computed tomography angiography showed all the aortic stent-grafts and chimney grafts to be patent. Favorable remodeling was observed at the level of maximum descending aorta and left subclavian artery with expansion of true lumen (from 18.4 ± 4.8 to 25 ± 0.86 mm, p < 0.001 and 27.1 ± 0.62 to 28.5 ± 0.37 mm, p < 0.001) and depressurization of false lumen (from 23.7 ± 2.7 to 8.7 ± 3.8 mm, p < 0.001, from 5.3 ± 1.2 to 2.1 ± 2.1 mm, p < 0.001). While at the level of maximum abdominal aorta, suboptimal remodeling of the total aorta (from 24.1 ± 0.4 to 23.6 ± 1.5 mm, p = 0.06) and true lumen (from 13.8 ± 0.6 to 14.5 ± 0.4 mm, p = 0.08) was observed.ConclusionBased on our limited experience, the chimney technique with thoracic endovascular repair is demonstrated to be promising for TBAD extending to the arch with favorable aortic remodeling.

  14. Proximal Probes Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Proximal Probes Facility consists of laboratories for microscopy, spectroscopy, and probing of nanostructured materials and their functional properties. At the...

  15. Body composition, fitness score and arterial stiffness assesment in a chronic hemodialysis population

    Directory of Open Access Journals (Sweden)

    Adelina Mihăescu

    2011-12-01

    Full Text Available Patients undergoing long-term hemodialysis have a high risk of cardiovascular disease. Arterial stiffness is highly prevalent in this type of patients. The aim of our study was to analyse the relationship between body composition, blood chemistries and arterial stiffness in a poorly fit population of chronic hemodialysed patients. Patients and methods involved measuring body composition and fitness score by multifrequence bioimpedance with the body composition analyzer InBody720 and arterial stiffness by the measurement of aortic Pulse Wave Velocity (PWVao and Aortic Augmentation Index (Aix using an oscillometric method on 65 HD patients; measurements were made before a midweek dialysis session. Results: PWVao correlated significantly with weight (p=0.01, r2=1.14, body fat mass (p=0.007, r2=0.14, abdominal circumference (p=0.01, r2=0.12 and with fitness score (p=0.01, r2=0.11. Aix correlated with weight (p<0.05, r2=0.25, intracellular, extracellular- and total body water (p<0.05, r2=0.24 with body protein, soft lean mass, minerals, fat free mass and skeletal muscle mass (p<0.05, r2= 0.3 and with serum calcium (p=0.005, r2=0.2. Conclusions: Arterial stiffness is a common feature of the hemodialysed patients, significantly related to the blood calcium, fitness score and the body composition, especially fat body mass.

  16. Traumatic aortic ruptures

    NARCIS (Netherlands)

    Balm, R.; Hoornweg, L. L.

    2005-01-01

    Most patients with a traumatic aortic rupture (TAR) were involved in high velocity motor vehicle accidents. initial management of these patients should be according to the guidelines of the advanced trauma life support group (ATLS). Patients with a suspected TAR are preferably managed by controlled

  17. Unoperated aortic aneurysm

    DEFF Research Database (Denmark)

    Perko, M J; Nørgaard, M; Herzog, T M

    1995-01-01

    From 1984 to 1993, 1,053 patients were admitted with aortic aneurysm (AA) and 170 (15%) were not operated on. The most frequent reason for nonoperative management was presumed technical inoperability. Survivals for patients with thoracic, thoracoabdominal, and abdominal AA were comparable. No sig...

  18. Tissue engineered aortic valve

    OpenAIRE

    Dohmen, P M

    2012-01-01

    Several prostheses are available to replace degenerative diseased aortic valves with unique advantages and disadvantages. Bioprotheses show excellent hemodynamic behavior and low risk of thromboembolic complications, but are limited by tissue deterioration. Mechanical heart valves have extended durability, but permanent anticoagulation is mandatory. Tissue engineering created a new generation heart valve, which overcome limitations of biological and mechanical heart valves due to remodelling,...

  19. Lase Ultrasonic Web Stiffness tester

    Energy Technology Data Exchange (ETDEWEB)

    Tim Patterson, Ph.D., IPST at Ga Tech

    2009-01-12

    The objective is to provide a sensor that uses non-contact, laser ultrasonics to measure the stiffness of paper during the manufacturing process. This will allow the manufacturer to adjust the production process in real time, increase filler content, modify fiber refining and as result produce a quality product using less energy. The sensor operates by moving back and forth across the paper web, at pre-selected locations firing a laser at the sheet, measuring the out-of-plane velocity of the sheet then using that measurement to calculate sheet stiffness.

  20. Vascular calcification and aortic fibrosis: a bifunctional role for osteopontin in diabetic arteriosclerosis.

    Science.gov (United States)

    Shao, Jian-Su; Sierra, Oscar L; Cohen, Richard; Mecham, Robert P; Kovacs, Attila; Wang, James; Distelhorst, Kathryn; Behrmann, Abraham; Halstead, Linda R; Towler, Dwight A

    2011-08-01

    Calcification and fibrosis reduce vascular compliance in arteriosclerosis. To better understand the role of osteopontin (OPN), a multifunctional protein upregulated in diabetic arteries, we evaluated contributions of OPN in male low-density lipoprotein receptor (LDLR)-/- mice fed a high-fat diet. OPN had no impact on high-fat diet-induced hyperglycemia, dyslipidemia, or body composition. However, OPN-/-;LDLR-/- mice exhibited an altered time-course of aortic calcium accrual-reduced during initiation but increased with progression-versus OPN+/+;LDLR-/- controls. Collagen accumulation, chondroid metaplasia, and mural thickness were increased in aortas of OPN-/-;LDLR-/- mice. Aortic compliance was concomitantly reduced. Vascular reexpression of OPN (SM22-OPN transgene) reduced aortic Col2A1 and medial chondroid metaplasia but did not affect atherosclerotic calcification, Col1A1 expression, collagen accumulation, or arterial stiffness. Dosing with the proinflammatory OPN fragment SVVYGLR upregulated aortic Wnt and osteogenic gene expression, increased aortic β-catenin, and restored early-phase aortic calcification in OPN-/-;LDLR-/- mice. OPN exerts stage-specific roles in arteriosclerosis in LDLR-/- mice. Actions phenocopied by the OPN metabolite SVVYGLR promote osteogenic calcification processes with disease initiation. OPN limits vascular chondroid metaplasia, endochondral mineralization, and collagen accumulation with progression. Complete deficiency yields a net increase in arteriosclerotic disease, reducing aortic compliance and conduit vessel function in LDLR-/- mice.

  1. Effects of Different Exercise Modes on Arterial Stiffness and Nitric Oxide Synthesis.

    Science.gov (United States)

    Hasegawa, Natsuki; Fujie, Shumpei; Horii, Naoki; Miyamoto-Mikami, Eri; Tsuji, Katsunori; Uchida, Masataka; Hamaoka, Takafumi; Tabata, Izumi; Iemitsu, Motoyuki

    2018-01-30

    Aerobic training (AT) and high-intensity intermittent training (HIIT) reduce arterial stiffness, whereas resistance training (RT) induces deterioration of or no change in arterial stiffness. However, the molecular mechanism of these effects of different exercise modes remains unclear. This study aimed to clarify the difference of different exercise effects on endothelial nitric oxide synthase (eNOS) signaling pathway and arterial stiffness in rats and humans. In the animal study, forty 10-week-old male Sprague-Dawley rats were randomly divided into 4groups: sedentary control (CON), AT (treadmill running, 60min at 30m/min, 5days/wk for 8weeks), RT (ladder-climbing, 8-10sets/day, 3days/wk for 8weeks), and HIIT (14repeats of 20-sec swimming session with 10-sec pause between sessions, 4days/wk for 6weeks from 12-week-old) groups (n=10 in each group). In the human study, we confirmed the effects of 6-week HIIT and 8-week AT interventions on central arterial stiffness and plasma nitrite/nitrate (NOx) level in untrained healthy young men in randomized controlled trial (HIIT, AT, and CON; n=7 in each group). In the animal study, the effect on aortic pulse wave velocity (PWV), as an index of central arterial stiffness, following HIIT was the same as the decrease in aortic PWV and increase in arterial eNOS/Akt phosphorylation following AT, which was not changed by RT. Negative correlation between aortic PWV and eNOS phosphorylation was observed (r=-0.38, pHIIT- and AT-induced changes in carotid-femoral PWV (HIIT -115.3±63.4 and AT -157.7±45.7 vs. CON 71.3±61.1 m/sec, each pHIIT may reduce central arterial stiffness via the increase in aortic NO bioavailability despite short time and short term and has the same effects as AT.

  2. Association of Gastrocnemius Muscle Stiffness With Passive Ankle Joint Stiffness and Sex-Related Difference in the Joint Stiffness.

    Science.gov (United States)

    Chino, Kintaro; Takashi, Hideyuki

    2017-11-15

    Passive ankle joint stiffness is affected by all structures located within and over the joint, and is greater in men than in women. Localized muscle stiffness can be assessed by ultrasound shear wave elastography, and muscle architecture such as fascicle length and pennation angle can be measured by B-mode ultrasonography. Thus, we assessed localized muscle stiffness of the medial gastrocnemius (MG) with consideration of individual variability in the muscle architecture, and examined the association of the muscle stiffness with passive ankle joint stiffness and the sex-related difference in the joint stiffness. Localized muscle stiffness of the MG in 16 men and 17 women was assessed at 10° and 20° plantar flexion, neutral anatomical position, 10° and 20° dorsiflexion. Fascicle length and pennation angle of the MG were measured at these joint positions. Passive ankle joint stiffness was determined by the ankle joint angle-torque relationship. Localized MG muscle stiffness was not significantly correlated with passive ankle joint stiffness, and did not show significant sex-related difference, even when considering the muscle architecture. This finding suggest that muscle stiffness of the MG would not be a prominent factor to determine passive ankle joint stiffness and the sex-related difference in the joint stiffness.

  3. A novel sax-stent method in treatment of ascending aorta and aortic arch aneurysms evaluated by finite element simulations.

    Science.gov (United States)

    Arokiaraj, M C; De Beule, M; De Santis, G

    2017-02-01

    A novel stent method to simplify treatment of proximal ascending aorta and aortic arch aneurysms was developed and investigated by finite element analysis. Therapy of ascending aortic and aortic arch aneurysms is difficult and challenging and is associated with various complications. A 55mm wide×120mm long stent was designed without the stent graft and the stent was deployed by an endovascular method in a virtual patient-specific aneurysm model. The stress-strain analysis and deployment characteristics were performed in a finite element analysis using the Abaqus software. The stent, when embedded in the aortic wall, significantly reduced aortic wall stresses, while preserving the side coronary ostia and side branches in the aortic arch. When tissue growth was modeled computationally over the stent struts the wall stresses in aorta was reduced. This effect became more pronounced when increasing the thickness of the tissue growth. There were no abnormal stresses in the aorta, coronary ostium and at the origin of aortic branches. The stent reduced aneurysm expansion cause by hypertensive condition from 2mm without stenting to 1.3mm after stenting and embedding. In summary, we uncovered a simple treatment method using a bare nitinol stent without stent graft in the treatment of the proximal aorta and aortic arch aneurysms, which could eventually replace the complex treatment methods for this disease. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  4. The mechanical benefit of medial support screws in locking plating of proximal humerus fractures.

    Science.gov (United States)

    Zhang, Wen; Zeng, Langqing; Liu, Yanjie; Pan, Yao; Zhang, Wei; Zhang, Changqing; Zeng, Bingfang; Chen, Yunfeng

    2014-01-01

    The purpose of this study was to evaluate the biomechanical advantages of medial support screws (MSSs) in the locking proximal humeral plate for treating proximal humerus fractures. Thirty synthetic left humeri were randomly divided into 3 subgroups to establish two-part surgical neck fracture models of proximal humerus. All fractures were fixed with a locking proximal humerus plate. Group A was fixed with medial cortical support and no MSSs; Group B was fixed with 3 MSSs but without medial cortical support; Group C was fixed with neither medial cortical support nor MSSs. Axial compression, torsional stiffness, shear stiffness, and failure tests were performed. Constructs with medial support from cortical bone showed statistically higher axial and shear stiffness than other subgroups examined (Pproximal humerus was not supported by medial cortical bone, locking plating with medial support screws exhibited higher axial and torsional stiffness than locking plating without medial support screws (P ≤ 0.0207). Specimens with medial cortical bone failed primarily by fracture of the humeral shaft or humeral head. Specimens without medial cortical bone support failed primarily by significant plate bending at the fracture site followed by humeral head collapse or humeral head fracture. Anatomic reduction with medial cortical support was the stiffest construct after a simulated two-part fracture. Significant biomechanical benefits of MSSs in locking plating of proximal humerus fractures were identified. The reconstruction of the medial column support for proximal humerus fractures helps to enhance mechanical stability of the humeral head and prevent implant failure.

  5. Genetics Home Reference: supravalvular aortic stenosis

    Science.gov (United States)

    ... Home Health Conditions Supravalvular aortic stenosis Supravalvular aortic stenosis Printable PDF Open All Close All Enable Javascript ... view the expand/collapse boxes. Description Supravalvular aortic stenosis (SVAS) is a heart defect that develops before ...

  6. [From stiff man syndrome to stiff person spectrum disorders].

    Science.gov (United States)

    Meinck, H-M; Balint, B

    2018-02-01

    The identification of new variants of the stiff man syndrome (SMS) and of new, probably pathogenic neuronal autoantibodies has led to the concept of stiff man (or person) spectrum disorders (SPSD). This is an expanding group of rare chronic autoimmune inflammatory diseases of the central nervous system (CNS) that have in common the main symptoms of fluctuating rigidity and spasms with pronounced stimulus sensitivity. These core symptoms are mandatory and can be accompanied by a wide variety of other neurological signs. The SPSDs are associated with autoantibodies directed against neuronal proteins that attenuate excitability. Neither clinical phenotypes nor the course of SPSD correlate closely with the antibody status. The treatment of these diseases aims at maintaining mobility and is pragmatically oriented to the degree of impediment and comprises antispastic, anticonvulsant and immunomodulating or immunosuppressive medication strategies.

  7. Neonatal aortic stenosis.

    Science.gov (United States)

    Turley, K; Bove, E L; Amato, J J; Iannettoni, M; Yeh, J; Cotroneo, J V; Galdieri, R J

    1990-04-01

    Aortic stenosis in the neonate has been associated in the past with a high operative mortality. As a result, in the current era of percutaneous balloon dilatation, the optimal mode of therapy remains controversial. An approach of stabilization with cardiopulmonary bypass, followed by relief of left ventricular outflow tract obstruction, was used at three institutions, and the results are presented. During the period 1983 to 1989, 40 neonates with isolated aortic stenosis and patent ductus arteriosus or coarctation of the aorta, or both, underwent operative therapy. Ages ranged from 1 to 30 days, median of 12 days, including 17 patients in the first week of life. There were 30 boys and 10 girls; weights ranged from 2.5 to 5.5 kg with a mean of 3.6 kg. Perioperative conditions included congestive heart failure in 38 and mitral regurgitation in 16; left ventricular-aortic gradients ranged from 15 to 130 mm Hg, with a mean of 67 mm Hg. There were 30 open valvotomies and 10 transventricular dilatations. The hospital survival rate was 87.5% (35/40) with no significant difference between the methods of valvotomy (9/10 in the transventricular dilatation group, 90%; 26/30 in the open valvotomy group, 87%). Although multiple methods of perfusion and valvotomy were used, the single unifying factor of cardiopulmonary bypass stabilization was present in all 40 patients. No significant difference in survival was noted between institutions, methods of cardiopulmonary bypass, cardiopulmonary bypass times, crossclamp times, or method of valvotomy. There have been five reoperations, with one late death in a patient requiring mitral valve replacement and an apical-aortic conduit. One sudden death occurred; autopsy revealed endocardial fibroelastosis. Results demonstrate that in the three institutions using the methods described, a high operative and late survival rate is possible. The results of this technique, against which percutaneous dilatation should be compared, are standard in

  8. Neonatal aortic stenosis.

    Science.gov (United States)

    Drury, Nigel E; Veldtman, Gruschen R; Benson, Lee N

    2005-09-01

    Neonatal aortic stenosis is a complex and heterogeneous condition, defined as left ventricular outflow tract obstruction at valvular level, presenting and often requiring treatment in the first month of life. Initial presentation may be catastrophic, necessitating hemodynamic, respiratory and metabolic resuscitation. Subsequent management is focused on maintaining systemic blood flow, either via a univentricular Norwood palliation or a biventricular route, in which the effective aortic valve area is increased by balloon dilation or surgical valvotomy. In infants with aortic annular hypoplasia but adequately sized left ventricle, the Ross-Konno procedure is also an attractive option. Outcomes after biventricular management have improved in recent years as a consequence of better patient selection, perioperative management and advances in catheter technology. Exciting new developments are likely to significantly modify the natural history of this disorder, including fetal intervention for the salvage of the hypoplastic left ventricle; 3D echocardiography providing better definition of valve morphology and aiding patient selection for a surgical or catheter-based intervention; and new transcutaneous approaches, such as duel beam echo, to perforate the valve.

  9. Energy-Efficient Variable Stiffness Actuators

    NARCIS (Netherlands)

    Visser, L.C.; Carloni, Raffaella; Stramigioli, Stefano

    2011-01-01

    Variable stiffness actuators are a particular class of actuators that is characterized by the property that the apparent output stiffness can be changed independent of the output position. To achieve this, variable stiffness actuators consist of a number of elastic elements and a number of actuated

  10. Shoulder Stiffness : Current Concepts and Concerns

    NARCIS (Netherlands)

    Itoi, Eiji; Arce, Guillermo; Bain, Gregory I.; Diercks, Ronald L.; Guttmann, Dan; Imhoff, Andreas B.; Mazzocca, Augustus D.; Sugaya, Hiroyuki; Yoo, Yon-Sik

    Shoulder stiffness can be caused by various etiologies such as immobilization, trauma, or surgical interventions. The Upper Extremity Committee of ISAKOS defined the term "frozen shoulder" as idiopathic stiff shoulder, that is, without a known cause. Secondary stiff shoulder is a term that should be

  11. A proposal for standardizing computed tomography reports on abdominal aortic aneurysms; Proposta para padronizacao do relatorio de tomografia computadorizada nos aneurismas da aorta abdominal

    Energy Technology Data Exchange (ETDEWEB)

    Torlai, Fabiola Goda; Meirelles, Gustavo S. Portes [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil); Miranda Junior, Fausto; Fonseca, Jose Honorio A.P. da [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Dept. de Cirurgia; Ajzen, Sergio; D' Ippolito, Giuseppe [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Dept. de Diagnostico por Imagem]. E-mail: giuseppe_dr@uol.com.br

    2006-07-15

    Objective: to propose a model to standardize computed tomography reports on abdominal aortic aneurysms. Materials and methods: interviews were carried out with members of the Vascular Surgery Division of our institution, in the period between April and October 2004, aiming at developing a standardized model of computed tomography reports on abdominal aortic aneurysms. Based on this model, a questionnaire was elaborated and sent to other nine surgeons, all of them experienced in the field of abdominal aortic surgery. The questionnaires response rate was 55.5% (5/9). Results: the most frequently mentioned parameters of interest for evaluation of abdominal aortic aneurysms were: maximum diameter of proximal aortic neck, proximal aortic neck length to lower renal arteries, shape of proximal aortic neck, maximum diameter of the aneurysm and diameter of the common iliac arteries. These data allowed the development of a proposal for a model to standardize computed tomography reports. Conclusion: a model for standardized tomographic analysis of abdominal aortic aneurysms has met vascular surgeons' needs for following-up patients and planning their treatment. (author)

  12. Dynamic stiffness of suction caissons

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Liingaard, Morten; Andersen, Lars

    This report concerns the dynamic soil-structure interaction of steel suction caissons applied as foundations for offshore wind turbines. An emphasis is put on torsional vibrations and coupled sliding/rocking motion, and the influence of the foundation geometry and the properties of the surrounding...... soil is examined. The soil is simplified as a homogenous linear viscoelastic material and the dynamic stiffness of the suction caisson is expressed in terms of dimensionless frequency-dependent coefficients corresponding to the different degrees of freedom. The dynamic stiffness coefficients...... for the skirted foundation are evaluated by means of a three-dimensional coupled boundary element/finite element model. Comparisons with known analytical and numerical solutions indicate that the static and dynamic behaviour of the foundation are predicted accurately with the applied model. The analysis has been...

  13. A personalized-model-based central aortic pressure estimation method.

    Science.gov (United States)

    Jiang, Sheng; Zhang, Zhi-Qiang; Wang, Fang; Wu, Jian-Kang

    2016-12-08

    Central Aortic Pressure (CAP) can be used to predict cardiovascular structural damage and cardiovascular events, and the development of simple, well-validated and non-invasive methods for CAP waveforms estimation is critical to facilitate the routine clinical applications of CAP. Existing widely applied methods, such as generalized transfer function (GTF-CAP) method and N-Point Moving Average (NPMA-CAP) method, are based on clinical practices, and lack a mathematical foundation. Those methods also have inherent drawback that there is no personalisation, and missing individual aortic characteristics. To overcome this pitfall, we present a personalized-model-based central aortic pressure estimation method (PM-CAP)in this paper. This PM-CAP has a mathematical foundation: a human aortic network model is proposed which is developed based on viscous fluid mechanics theory and could be personalized conveniently. Via measuring the pulse wave at the proximal and distal ends of the radial artery, the least square method is then proposed to estimate patient-specific circuit parameters. Thus the central aortic pulse wave can be obtained via calculating the transfer function between the radial artery and central aorta. An invasive validation study with 18 subjects comparing PM-CAP with direct aortic root pressure measurements during percutaneous transluminal coronary intervention was carried out at the Beijing Hospital. The experimental results show better performance of the PM-CAP method compared to the GTF-CAP method and NPMA-CAP method, which illustrates the feasibility and effectiveness of the proposed method. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Factors and forces influencing stent-graft migration after endovascular aortic aneurysm repair.

    NARCIS (Netherlands)

    Mohan, I.V.; Harris, P.L.; Marrewijk, C.J. van; Laheij, R.J.F.; How, T.V.

    2002-01-01

    Purpose: To assess and validate the clinical features predisposing to stent-graft migration and to calculate the distal displacement forces exerted at the proximal fixation site following endovascular aortic aneurysm repair (EVAR). Methods: Demographic, anatomical, and graft-related features from

  15. Tissue Transglutaminase Modulates Vascular Stiffness and Function Through Crosslinking-Dependent and Crosslinking-Independent Functions.

    Science.gov (United States)

    Steppan, Jochen; Bergman, Yehudit; Viegas, Kayla; Armstrong, Dinani; Tan, Siqi; Wang, Huilei; Melucci, Sean; Hori, Daijiro; Park, Sung Yong; Barreto, Sebastian F; Isak, Abraham; Jandu, Sandeep; Flavahan, Nicholas; Butlin, Mark; An, Steven S; Avolio, Alberto; Berkowitz, Dan E; Halushka, Marc K; Santhanam, Lakshmi

    2017-02-03

    The structural elements of the vascular wall, namely, extracellular matrix and smooth muscle cells (SMCs), contribute to the overall stiffness of the vessel. In this study, we examined the crosslinking-dependent and crosslinking-independent roles of tissue transglutaminase (TG2) in vascular function and stiffness. SMCs were isolated from the aortae of TG2-/- and wild-type (WT) mice. Cell adhesion was examined by using electrical cell-substrate impedance sensing and PicoGreen assay. Cell motility was examined using a Boyden chamber assay. Cell proliferation was examined by electrical cell-substrate impedance sensing and EdU incorporation assays. Cell micromechanics were studied using magnetic torsion cytometry and spontaneous nanobead tracer motions. Aortic mechanics were examined by tensile testing. Vasoreactivity was studied by wire myography. SMCs from TG2-/- mice had delayed adhesion, reduced motility, and accelerated de-adhesion and proliferation rates compared with those from WT. TG2-/- SMCs were stiffer and displayed fewer cytoskeletal remodeling events than WT. Collagen assembly was delayed in TG2-/- SMCs and recovered with adenoviral transduction of TG2. Aortic rings from TG2-/- mice were less stiff than those from WT; stiffness was partly recovered by incubation with guinea pig liver TG2 independent of crosslinking function. TG2-/- rings showed augmented response to phenylephrine-mediated vasoconstriction when compared with WT. In human coronary arteries, vascular media and plaque, high abundance of fibronectin expression, and colocalization with TG2 were observed. TG2 modulates vascular function/tone by altering SMC contractility independent of its crosslinking function and contributes to vascular stiffness by regulating SMC proliferation and matrix remodeling. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  16. Staged endovascular repair of thoracoabdominal aortic aneurysms limits incidence and severity of spinal cord ischemia.

    Science.gov (United States)

    O'Callaghan, Adrian; Mastracci, Tara M; Eagleton, Matthew J

    2015-02-01

    Neurologic dysfunction remains a persistent complication of extensive aortic repair owing to disruption of the spinal collateral network. We hypothesized that staged repair might mitigate the incidence and severity of this spinal cord ischemia (SCI). We conducted a retrospective cohort study of patients undergoing a Crawford type II repair of a thoracoabdominal aortic aneurysm between January 2008 and July 2013. Baseline demographics, incidence of prior aortic surgery, comorbidities, and outcomes were prospectively recorded. Staged repair was defined as intentional completion of the endovascular repair as two temporally separate procedures, referred to as a two-stage repair. Extent of aortic cover was calculated by three-dimensional imaging and reported as the proportion of the aorta covered between the left subclavian artery and the aortic bifurcation. Primary outcome measures were incidence and severity of SCI and mortality. The study included 87 patients, divided into the following subgroups: single-stage repair (n = 32; repair in a single procedure, without prior aortic surgery), two-stage repair (n = 27; repair in two separate procedures, without prior aortic surgery), and unintentionally staged repair (n = 28; those with prior aortic surgery, without an intention to stage). Median time between stages was 5 months (range, 1-60 months). All groups were equivalent in terms of demographics and risk factors; however, the staged group had significantly greater proximal aortic cover (P = .001). The overall rates of SCI in the nonstaged and staged groups were 37.5% (12 of 32) and 11.1% (3 of 27), respectively (P = .03). Furthermore, all neurologic injuries in the staged group were temporary. The 30-day survival in the single-stage, two-stage, and unintentionally staged repairs was 18.8%, 0%, and 10.7%, respectively (P = .52). Staged repair appears both to protect against SCI and to enhance overall survival in extensive aortic repair. Copyright © 2015 Society for

  17. Selective cerebral perfusion with aortic cannulation and short-term hypothermic circulatory arrest in aortic arch reconstruction.

    Science.gov (United States)

    Turkoz, R; Saritas, B; Ozker, E; Vuran, C; Yoruker, U; Balci, S; Altun, D; Turkoz, A

    2014-01-01

    The deep hypothermic circulatory arrest (DHCA) technique has been used in aortic arch and isthmus hypoplasia for many years. However, with the demonstration of the deleterious effects of prolonged DHCA, selective cerebral perfusion (SCP) has started to be used in aortic arch repair. For SCP, perfusion via the innominate artery route is generally preferred (either direct innominate artery cannulation or re-routing of the cannula in the aorta is used). Herein, we describe our technique and the result of arch reconstruction in combination with selective cerebral and myocardial perfusion (SCMP) and short-term total circulatory arrest (TCA) (5-10 min) through ascending aortic cannulation. Thirty-seven cases with aortic arch and isthmus hypoplasia accompanying cardiac defects were operated on with SCMP and short TCA in Baskent University Istanbul Research and Training Hospital between January 2007 and Sep 2012. There were 17 cases with ventricular septal defect (VSD)-coarctation with aortic arch hypoplasia (CoAAH), 4 cases of transposition of the great arteries-VSD-CoAAH, 4 cases of Taussing Bing Anomaly-CoAAH, 2 cases complete atrioventricular canal defect-CoAAH, 3 cases single ventricle-CoAAH, 3 cases of type A interruption-VSD, 2 subvalvular aortic stenosis-CoAAH and 2 cases of isolated CoAAH. The aorta was cannulated in the middle of the ascending aorta in all cases. The cross-clamp was applied to the aortic arch distal to either the innominate artery or the left carotid artery. In addition, a side-biting clamp was applied to the descending aorta. The aorta between these two clamps was reconstructed with gluteraldehyde-treated autogeneous pericardium, using SCMP. The proximal arch and distal ascending aorta reconstructions were carried out under short TCA. The mean age of the patients was 2.5 ± 2 months. The mean cardiopulmonary bypass and cross-clamp times were 144 ± 58 and 43 ± 27 minutes, respectively. The mean SCMP and descending aorta ischemia times were 22

  18. Aortic stentgrafts and en dovascular abdominal aortic aneurysm repair

    African Journals Online (AJOL)

    2007-07-19

    Jul 19, 2007 ... 4). Calibrating angiography, transoesophageal echo and intravascular ultrasound (IVUS) are useful adjuncts only for thoracic aortic pathology. The stentgraft should generally be oversized by 15 - 20% (10 -. 15% for connective tissue disorders, aortic dissections, etc.). EVAR is performed with local, regional.

  19. Negative stiffness in gear contact

    Directory of Open Access Journals (Sweden)

    Půst L.

    2015-12-01

    Full Text Available The tooth contact stiffness is very often included in dynamic mathematical models of gear drives. It is an important value for calculation of torsion eigenfrequencies as well as the dynamic properties of the whole transmission systems. Planetary gear drives have several advantages over simple parallel axis gears, especially due to theirs compact design and great torque-to-weight ratio caused by multiple parallel paths. However, the dimensional or mounting errors can cause that some planets have the tendency to take more load than the others. One of the ways how to improve load sharing is the application of flexible planetary pins or by using a free central wheel. However in such cases, the wheels motion is defined in one rotation coordinate and two translation coordinates — tangential and radial. The reaction force at radial change of axis distance is usually neglected. The focus of this contribution is to derive the stiffness of this radial connection and to analyse the influence of radial stiffness on planetary gear dynamics.

  20. Right circumflex retro-oesophageal aortic arch with coarctation of a high-positioned right arch

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Kyung-Sik; Yong, Hwan Seok; Woo, Ok Hee; Kang, Eun-Young [Korea University Guro Hospital, Department of Radiology, Seoul (Korea); Lee, Joo-Won [Korea University Guro Hospital, Department of Paediatrics, Seoul (Korea)

    2007-06-15

    We present a rare case of right circumflex retro-oesophageal aortic arch with coarctation of a high-positioned right arch. A 7-month-old boy presented with a cardiac murmur. Cardiac situs was normal and there was no evidence of an intracardiac shunt or patent ductus arteriosus. MR aortography revealed a right aortic arch that was high-positioned, tortuous and narrowed. This right aortic arch crossed the midline behind the oesophagus and continued as a left-sided descending aorta. The left common carotid and subclavian arteries arose from a large branching vascular structure that derived from the top of the left-sided descending aorta. The right common carotid artery arose from the ascending aorta. The proximal portion of the right common carotid artery showed very severe stenosis and poststenotic dilatation. The right subclavian artery originated distal to the narrowed and tortuous segment of the aortic arch. (orig.)

  1. Decreased Aortic Elasticity in Children With Marfan Syndrome or Loeys-Dietz Syndrome.

    Science.gov (United States)

    Akazawa, Yohei; Motoki, Noriko; Tada, Akira; Yamazaki, Shoko; Hachiya, Akira; Matsuzaki, Satoshi; Kamiya, Motoko; Nakamura, Tomohiko; Kosho, Tomoki; Inaba, Yuji

    2016-10-25

    The characteristics of aortic elasticity are unclear in children with connective tissue disorders (CTDs) such as Marfan syndrome (MFS) and Loeys-Dietz syndrome (LDS), especially in those with a non-dilated aortic root (AoR). This study evaluated the aortic elasticity properties of pediatric MFS and LDS patients with either dilated or non-dilated AoR.Methods and Results:The 31 children with MFS or LDS were classified into dilated (Z score of AoR diameter ≥2.5; n=17) or non-dilated (Z score of AoR diameter elasticity parameters of distensibility, strain, and stiffness index at the levels of the AoR, sinotubular junction, ascending aorta, and descending aorta. Aortic distensibility and strain were significantly lower in both test groups than in controls at the AoR level. The Z score of AoR diameter significantly correlated with aortic distensibility (R=-0.63, Pelasticity at the level of the AoR may be decreased in children with MFS or LDS even before AoR dilatation progresses. Less aortic distensibility and CTD type are considered important parameters in estimating AoR dilatation in these patients. (Circ J 2016; 80: 2369-2375).

  2. Casein improves brachial and central aortic diastolic blood pressure in overweight adolescents: a randomised, controlled trial

    DEFF Research Database (Denmark)

    Arnberg, Karina; Larnkjær, Anni; Michaelsen, Kim F.

    2013-01-01

    Arterial stiffness, blood pressure (BP) and blood lipids may be improved by milk in adults and the effects may be mediated via proteins. However, limited is known about the effects of milk proteins on central aortic BP and no studies have examined the effects in children. Therefore, the present...... trial examined the effect of milk and milk proteins on brachial and central aortic BP, blood lipids, inflammation and arterial stiffness in overweight adolescents. A randomised controlled trial was conducted in 193 overweight adolescents aged 12–15 years. They were randomly assigned to drink 1 litre...... of water, skimmed milk, whey or casein for 12 weeks. The milk-based test drinks contained 35 g protein/l. The effects were compared with the water group and a pretest control group consisting of thirty-two of the adolescents followed 12 weeks before the start of the intervention. Outcomes were brachial...

  3. Effects of Enhanced External Counterpulsation on Arterial Stiffness and Myocardial Oxygen Demand in Patients with Chronic Angina Pectoris

    OpenAIRE

    Darren P. Casey; Beck, Darren T; Nichols, Wilmer W.; Conti, C. Richard; Choi, Calvin Y.; Khuddus, Matheen A.; Braith, Randy W.

    2011-01-01

    Enhanced external counterpulsation (EECP) is a non-invasive modality for treatment of symptomatic coronary disease (CAD) in patients not amenable to revascularization procedures. However, the mechanism(s) underlying the benefits of EECP remain unknown. We hypothesized that reductions in arterial stiffness and aortic wave reflection are a therapeutic target for EECP. CAD patients with chronic angina pectoris were randomized (2:1 ratio) to either 35 1-hr sessions of EECP (n=28) or Sham-EECP (n=...

  4. Shoulder stiffness and rotator cuff repair.

    Science.gov (United States)

    Papalia, Rocco; Franceschi, Francesco; Vasta, Sebastiano; Gallo, Andrea; Maffulli, Nicola; Denaro, Vincenzo

    2012-01-01

    Shoulder stiffness is a frequent complication of surgical repair of rotator cuff tears. Post-operative stiffness negatively affects surgical outcomes leading to a substantial comorbidity and to the failure of surgical treatment. Also, a stiff shoulder could commonly be concomitant with an rotator cuff tear (RCT). We performed a comprehensive search of CINAHL, Embase, Medline and the Cochrane Central Registry of Controlled Trials, from inception of the database to 31 July 2011. Sixteen articles published in peer-reviewed journals were included in this comprehensive review. The management of shoulder stiffness is still controversial. The role of rehabilitation programs (standard versus early passive mobilization) after RCT repair on the development of stiffness is not clear, while the role of arthroscopic capsular release for post-operative stiffness is better defined, although a threshold of decreased the range of movement for which capsular release is advised has not been identified. Several factors have been identified to predispose the development of shoulder stiffness. There is also evidence in favor of surgical management of RCTs even when accompanied by shoulder stiffness, and there are strong evidences that arthroscopic capsular release is reliable and effective in managing shoulder stiffness. The post-operative rehabilitation protocol remains controversial. We are still far from definitive guidelines for the management of pre- and post-operative stiffness, and prospective double-blinded randomized clinical trials are needed to obtain evidence allowing to establish a reliable and effective management plan for shoulder stiffness.

  5. Aortic Diameter Growth in Children With a Bicuspid Aortic Valve.

    Science.gov (United States)

    Merkx, Remy; Duijnhouwer, Anthonie L; Vink, Evelien; Roos-Hesselink, Jolien W; Schokking, Michiel

    2017-07-01

    Knowledge of aortic growth in patients with bicuspid aortic valve (BAV) is essential to identify patients at risk for dissection, but data on children remain unclear. We retrospectively evaluated the aortic diameters of all pediatric BAV patients, identified through an echocardiographic database (2005 to 2013). Medical records were reviewed and aortic diameters re-measured on echocardiographic images at diagnosis and if available on variable mid- and endpoints follow-up. Dilatation (z-score >2) was based on 2 different z-score equation methods (Gautier/Campens). In 234 of the total 250 BAV patients, aortic diameters were analyzed; median age was 6.1 years (interquartile range 1.7 to 10), of which 63% were male. Aortic coarctation was present in 81 (36%) patients, 23% had a ventricular septal defect. BAV morphology according to Sievers was as follows: type 0 in 128 patients (55%), type 1 in 96 (41%), and type 2 in 10 (4%). Ascending aortic (AA) dilatation was present in 24% (Gautier) and 36% (Campens) at inclusion. Median follow-up was 4.7 years. The AA was the only location where mean z-scores progressed significantly with age: 0.06 (Gautier) and 0.09 (Campens) units per year between ages 5 and 15 years. Associations for higher AA z-scores at older age were an initial z-score >2 (p aortic valve stenosis (p aortic surgery occurred. In conclusion, only the AA seems at risk for complication, although no aortic complications occurred in this pediatric BAV cohort. BAV morphology seems associated with larger AA z-scores and valvular dysfunction. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  6. Factors related to the effectiveness of variable stiffness colonoscope: results of a multivariate analysis

    Directory of Open Access Journals (Sweden)

    Javier Sola-Vera

    2014-01-01

    Full Text Available Background: Various studies and two meta-analysis have shown that a variable stiffness colonoscope improves cecal intubation rate. However, there are few studies on how this colonoscope should be used. Objective: The aim of this study was to identify factors related to the advancement of the colonoscope when the variable stiffness function is activated. Methods: Prospective study enrolling consecutive patients referred for colonoscopy. The variable stiffness colonoscope (Olympus CF-H180DI/L® was used. We performed univariate and multivariate analyses of factors associated with the success of the variable stiffness function. Results: After the data inclusion period, 260 patients were analyzed. The variable stiffness function was used most in the proximal colon segments (ascending and transverse colon 85 %; descending/sigmoid colon 15.2 %. The body mass index was lower in patients in whom the endoscope advanced after activating the variable stiffness than those in which it could not be advanced (25.9 ± 4.8 vs. 28.3 ± 5.4 kg/m², p = 0.009. The endoscope advanced less frequently when the stiffness function was activated in the ascending colon versus activation in other segments of the colon (25 % vs. 64.5 % ascending colon vs. other segments; p < 0.05. In the multivariate analysis, only the colon segment in which the variable stiffness was activated was an independent predictor of advancement of the colonoscope. Conclusions: The variable stiffness function is effective, allowing the colonoscope advancement especially when applied in the transverse colon, descending colon and sigmoid. However, when used in the ascending colon it has a lower effectiveness.

  7. Minimally invasive aortic valve replacement

    DEFF Research Database (Denmark)

    Foghsgaard, Signe; Schmidt, Thomas Andersen; Kjaergard, Henrik K

    2009-01-01

    In this descriptive prospective study, we evaluate the outcomes of surgery in 98 patients who were scheduled to undergo minimally invasive aortic valve replacement. These patients were compared with a group of 50 patients who underwent scheduled aortic valve replacement through a full sternotomy...

  8. Normal values of aortic dimensions, distensibility, and pulse wave velocity in children and young adults: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Voges Inga

    2012-11-01

    Full Text Available Abstract Background Aortic enlargement and impaired bioelasticity are of interest in several cardiac and non-cardiac diseases as they can lead to cardiovascular complications. Cardiovascular magnetic resonance (CMR is increasingly accepted as a noninvasive tool in cardiovascular evaluation. Assessment of aortic anatomy and bioelasticity, namely aortic distensibility and pulse wave velocity (PWV, by CMR is accurate and reproducible and could help to identify anatomical and bioelastic abnormalities of the aorta. However, normal CMR values for healthy children and young adults are lacking. Methods Seventy-one heart-healthy subjects (age 16.4 ± 7.6 years, range 2.3 - 28.3 years were examined using a 3.0 Tesla CMR scanner. Aortic cross-sectional areas and aortic distensibility were measured at four positions of the ascending and descending thoracic aorta. PWV was assessed from aortic blood flow velocity measurements in a aortic segment between the ascending aorta and the proximal descending aorta. The Lambda-Mu-Sigma (LMS method was used to obtain percentile curves for aortic cross-sectional areas, aortic distensibility and PWV according to age. Results Aortic areas, PWV and aortic distensibility (aortic cross-sectional areas: r = 0.8 to 0.9, p  Conclusions This study provides percentile curves for cross-sectional areas, distensibility and pulse wave velocity of the thoracic aorta in children and young adolescents between their 3rd and 29th year of life. These data may serve as a reference for the detection of pathological changes of the aorta in cardiovascular disease.

  9. Capacitive proximity sensor

    Science.gov (United States)

    Kronberg, James W.

    1994-01-01

    A proximity sensor based on a closed field circuit. The circuit comprises a ring oscillator using a symmetrical array of plates that creates an oscillating displacement current. The displacement current varies as a function of the proximity of objects to the plate array. Preferably the plates are in the form of a group of three pair of symmetric plates having a common center, arranged in a hexagonal pattern with opposing plates linked as a pair. The sensor produces logic level pulses suitable for interfacing with a computer or process controller. The proximity sensor can be incorporated into a load cell, a differential pressure gauge, or a device for measuring the consistency of a characteristic of a material where a variation in the consistency causes the dielectric constant of the material to change.

  10. Neighborhoods and manageable proximity

    Directory of Open Access Journals (Sweden)

    Stavros Stavrides

    2011-08-01

    Full Text Available The theatricality of urban encounters is above all a theatricality of distances which allow for the encounter. The absolute “strangeness” of the crowd (Simmel 1997: 74 expressed, in its purest form, in the absolute proximity of a crowded subway train, does not generally allow for any movements of approach, but only for nervous hostile reactions and submissive hypnotic gestures. Neither forced intersections in the course of pedestrians or vehicles, nor the instantaneous crossing of distances by the technology of live broadcasting and remote control give birth to places of encounter. In the forced proximity of the metropolitan crowd which haunted the city of the 19th and 20th century, as well as in the forced proximity of the tele-presence which haunts the dystopic prospect of the future “omnipolis” (Virilio 1997: 74, the necessary distance, which is the stage of an encounter between different instances of otherness, is dissipated.

  11. Predictors of aortic growth in uncomplicated type B aortic dissection from the Acute Dissection Stent Grafting or Best Medical Treatment (ADSORB) database

    DEFF Research Database (Denmark)

    Kamman, Arnoud V; Brunkwall, Jan; Verhoeven, Eric L

    2017-01-01

    database. Furthermore, we looked for trends in outcome for aortic growth and remodeling after BMT and thoracic endovascular aortic repair (TEVAR) and BMT (TEVAR+BMT). METHODS: BMT patients with available baseline and a 1-year follow-up arterial computed tomography scan were identified. True lumen and false...... interval, 0.813-1.00; P = .0502). The proximal sections A and B showed complete thrombosis in 80.6% in the BMT+TEVAR group compared with 9.5% in the BMT group. In these sections, changes from patent to partial or partial to complete thrombosis were observed in 90.3% of the TEVAR+BMT group vs 31...

  12. Atrofia muscular proximal familiar

    Directory of Open Access Journals (Sweden)

    José Antonio Levy

    1962-09-01

    Full Text Available Os autores relatam dois casos de atrofia muscular proximal familiar, moléstia caracterizada por déficit motor e atrofias musculares de distribuição proximal, secundárias a lesão de neurônios periféricos. Assim, como em outros casos descritos na literatura, foi feito inicialmente o diagnóstico de distrofia muscular progressiva. O diagnóstico correto foi conseguido com auxílio da eletromiografia e da biopsia muscular.

  13. Abdominal Aortic Emergencies.

    Science.gov (United States)

    Lech, Christie; Swaminathan, Anand

    2017-11-01

    This article discusses abdominal aortic emergencies. There is a common thread of risk factors and causes of these diseases, including age, male gender, hypertension, dyslipidemia, and connective tissue disorders. The most common presenting symptom of these disorders is pain, usually in the chest, flank, abdomen, or back. Computed tomography scan is the gold standard for diagnosis of pathologic conditions of the aorta in the hemodynamically stable patient. Treatment consists of a combination of blood pressure and heart rate control and, in many cases, emergent surgical intervention. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Abdominal aortic aneurysm surgery

    DEFF Research Database (Denmark)

    Gefke, K; Schroeder, T V; Thisted, B

    1994-01-01

    The goal of this study was to identify patients who need longer care in the ICU (more than 48 hours) following abdominal aortic aneurysm (AAA) surgery and to evaluate the influence of perioperative complications on short- and long-term survival and quality of life. AAA surgery was performed in 553......, 78% stated that their quality of life had improved or was unchanged after surgery and had resumed working. These data justify a therapeutically aggressive approach, including ICU therapy following AAA surgery, despite failure of one or more organ systems....

  15. Sweet potato (Ipomoea batatas) attenuates diet-induced aortic stiffening independent of changes in body composition.

    Science.gov (United States)

    Garner, Tyler; Ouyang, An; Berrones, Adam J; Campbell, Marilyn S; Du, Bing; Fleenor, Bradley S

    2017-08-01

    We hypothesized a sweet potato intervention would prevent high-fat (HF) diet-induced aortic stiffness, which would be associated with decreased arterial oxidative stress and increased mitochondrial uncoupling. Young (8-week old) C57BL/6J mice were randomly divided into 4 groups: low fat (LF; 10% fat), HF (60% fat), low-fat sweet potato (LFSP; 10% fat containing 260.3 μg/kcal sweet potato), or high-fat sweet potato diet (HFSP; 60% fat containing 260.3 μg/kcal sweet potato) for 16 weeks. Compared with LF and LFSP, HF- and HFSP-fed mice had increased body mass and percent fat mass with lower percent lean mass (all, P Sweet potato intervention did not influence body composition (all, P > 0.05). Arterial stiffness, assessed by aortic pulse wave velocity and ex vivo mechanical testing of the elastin region elastic modulus (EEM) was greater in HF compared with LF and HFSP animals (all, P sweet potato attenuates diet-induced aortic stiffness independent of body mass and composition, which is associated with a normalization of arterial oxidative stress possibly due to mitochondrial uncoupling.

  16. On the estimation of total arterial compliance from aortic pulse wave velocity.

    Science.gov (United States)

    Vardoulis, Orestis; Papaioannou, Theodore G; Stergiopulos, Nikolaos

    2012-12-01

    Total arterial compliance (C(T)) is a main determinant of cardiac afterload, left ventricular function and arterio-ventricular coupling. C(T) is physiologically more relevant than regional aortic stiffness. However, direct, in vivo, non-invasive, measurement of C(T) is not feasible. Several methods for indirect C(T) estimation require simultaneous recording of aortic flow and pressure waves, limiting C(T) assessment in clinical practice. In contrast, aortic pulse wave velocity (aPWV) measurement, which is considered as the "gold standard" method to assess arterial stiffness, is noninvasive and relatively easy. Our aim was to establish the relation between aPWV and C(T). In total, 1000 different hemodynamic cases were simulated, by altering heart rate, compliance, resistance and geometry using an accurate, distributed, nonlinear, one-dimensional model of the arterial tree. Based on Bramwell-Hill theory, the formula C(T) = k • aPWV(-2) was found to accurately estimate C(T) from aPWV. Coefficient k was determined both analytically and by fitting C(T) vs. aPWV data. C(T) estimation may provide an additional tool for cardiovascular risk (CV) assessment and better management of CV diseases. C(T) could have greater impact in assessing elderly population or subjects with elevated arterial stiffness, where aPWV seem to have limited prognostic value. Further clinical studies should be performed to validate the formula in vivo.

  17. [Experimental proximal carpectomy. Biodynamics].

    Science.gov (United States)

    Kuhlmann, J N

    1992-01-01

    Proximal carpectomy was performed in 10 fresh cadavre wrists. Dynamic x-rays were taken and the forces necessary to obtain different movements before and after the operation were measured. Comparison of these parameters clearly defines the advantages and limitations of carpectomy and indicates the reasons.

  18. Proximate Analysis of Coal

    Science.gov (United States)

    Donahue, Craig J.; Rais, Elizabeth A.

    2009-01-01

    This lab experiment illustrates the use of thermogravimetric analysis (TGA) to perform proximate analysis on a series of coal samples of different rank. Peat and coke are also examined. A total of four exercises are described. These are dry exercises as students interpret previously recorded scans. The weight percent moisture, volatile matter,…

  19. Proximal Tibial Bone Graft

    Science.gov (United States)

    ... the Big Toe Ailments of the Smaller Toes Diabetic Foot Treatments Currently selected Injections and other Procedures Treatments ... from which the bone was taken if the foot/ankle surgeries done at the same time allow for it. ... problems after a PTBG include infection, fracture of the proximal tibia and pain related ...

  20. [Paravalvular aortic regurgitation after transcatheter aortic valve replacement].

    Science.gov (United States)

    Buğan, Barış; Tuzcu, Emin Murat

    2014-01-01

    Transcatheter aortic valve replacement (TAVR) is a rapidly evolving technology that has been accepted as a treatment option in patients with severe aortic stenosis who are not suitable for or are at high risk for conventional surgery. Randomized trials have shown that TAVR decreases mortality and improves quality of life in patients who are not suitable for conventional surgery and that TAVR is not inferior to standard surgery in operable but high- risk patients. However, TAVR has several important limitations, the most prominent of which is residual paravalvular aortic regurgitation (PAR). The purpose of this review is to present the mechanism, incidence, assessment, and treatment of PAR after TAVR.

  1. Reinforced aortic root reconstruction for acute type A aortic dissection involving the aortic root

    Directory of Open Access Journals (Sweden)

    Han Qing-qi

    2013-06-01

    Full Text Available OBJECTIVE: There are debates regarding the optimal approach for AAAD involving the aortic root. We described a modified reinforced aortic root reconstruction approach for treating AAAD involving the aortic root. METHODS: A total of 161 patients with AAAD involving the aortic root were treated by our modified reinforced aortic root reconstruction approach from January 1998 to December 2008. Key features of our modified approach were placement of an autologous pericardial patch in the false lumen, lining of the sinotubular junction lumen with a polyester vascular ring, and wrapping of the vessel with Teflon strips. Outcome measures included post-operative mortality, survival, complications, and level of aortic regurgitation. RESULTS: A total of 161 patients were included in the study (mean age: 43.3 1 15.5 years. The mean duration of follow-up was 5.1 1 2.96 years (2-12 years. A total of 10 (6.2% and 11 (6.8% patients died during hospitalization and during follow-up, respectively. Thirty-one (19.3% patients experienced postoperative complications. The 1-, 3-, 5-, and 10-year survival rates were 99.3%, 98%, 93.8%, and 75.5%, respectively. There were no instances of recurrent aortic dissection, aortic aneurysm, or pseudoaneurysm during the entire study period. The severity of aortic regurgitation dramatically decreased immediately after surgery (from 28.6% to 0% grade 3-4 and thereafter slightly increased (from 0% to 7.2% at 5 years and 9.1% at 10 years. CONCLUSION: This modified reinforced aortic root reconstruction was feasible, safe and durable/effective, as indicated by its low mortality, low postoperative complications and high survival rate.

  2. Carotid β-stiffness index is associated with slower processing speed but not working memory or white matter integrity in healthy middle-aged/older adults.

    Science.gov (United States)

    DuBose, Lyndsey E; Voss, Michelle W; Weng, Timothy B; Kent, James D; Dubishar, Kaitlyn M; Lane-Cordova, Abbi; Sigurdsson, Gardar; Schmid, Phillip; Barlow, Patrick B; Pierce, Gary L

    2017-04-01

    Aging is associated with increased carotid artery stiffness, a predictor of incident stroke, and reduced cognitive performance and brain white matter integrity (WMI) in humans. Therefore, we hypothesized that higher carotid stiffness/lower compliance would be independently associated with slower processing speed, higher working memory cost, and lower WMI in healthy middle-aged/older (MA/O) adults. Carotid β-stiffness (P adults. MA/O adults demonstrated slower processing speed (27.4 ± 4.6 vs. 35.4 ± 5.0 U/60 s, P working memory cost (-15.4 ± 0.14 vs. -2.2 ± 0.05%, P adults. Global WMI was lower in MA/O adults (P working memory cost or WMI. Among MA/O adults, higher β-stiffness (B = -0.60 ± 0.18, P = 0.002) and lower compliance (B = 0.93 ± 0.26, P = 0.002) were associated with slower processing speed but not working memory cost or WMI. These data suggest that greater carotid artery stiffness is independently and selectively associated with slower processing speed but not working memory among MA/O adults. Carotid artery stiffening may modulate reductions in processing speed earlier than working memory with healthy aging in humans.NEW & NOTEWORTHY Previously, studies investigating the relation between large elastic artery stiffness, cognition, and brain structure have focused mainly on aortic stiffness in aged individuals with cardiovascular disease risk factors and other comorbidities. This study adds to the field by demonstrating that the age-related increases in carotid artery stiffness, but not aortic stiffness, is independently and selectively associated with slower processing speed but not working memory among middle-aged/older adults with low cardiovascular disease risk factor burden. Copyright © 2017 the American Physiological Society.

  3. Measurement of the aortic diameter in the asymptomatic Korean population: Assessment with multidetector CT

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Hwan; Lee, Whal; Choi, Hyuck Jae; Kim, Dae Jin; Park, Eun Ah; Chung, Jin Wook; Park, Jae Hyung [Dept. of Radiology, Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2013-08-15

    To determine normal reference values for aortic diameters in asymptomatic Korean adults. Three hundred adults without signs or symptoms of cardiovascular diseases were enrolled in this study. Aortic diameters were measured at nine predetermined levels on CT images. Aortic diameter measurements were adjusted for body surface area. Analysis of data was performed with regard to age, sex, weight, height and hypertension. Aortic diameters were 2.99 ± 0.57 cm at the ascending aorta, 2.54 ± 0.35 cm at the transverse aortic arch, 2.36 ± 0.35 cm at the proximal descending thoracic aorta (DTA), 2.23 ± 0.37 cm at the mid DTA, 2.17 ± 0.38 cm at the distal DTA, 2.16 ± 0.37 cm at the thoracoabdominal junction, 2.10, 00B1, 0.35 cm at the level of the celiac axis, 1.94, 00B1, 0.36 cm at the suprarenal aorta, 1.58 ± 0.24 cm at the aortic bifurcation. Men had slightly larger diameters than women (p < 0.05). All diameters increased with age and hypertension, with statistical significance (p < 0.01). And all aortic diameters increased with height (p < 0.05) except at the level of the aortic arch (p = 0.056), and increased with weight (p < 0.05) except at the level of the suprarenal aorta (p = 0.067). Male sex, higher weight and height, age and hypertension are associated with larger aortic diameters in asymptomatic Korean adults.

  4. Vascular Aging and Arterial Stiffness

    Directory of Open Access Journals (Sweden)

    Luana de Rezende Mikael

    Full Text Available Abstract Cardiovascular diseases (CVD account annually for almost one third of all deaths worldwide. Among the CVD, systemic arterial hypertension (SAH is related to more than half of those outcomes. Type 2 diabetes mellitus is an independent risk factor for SAH because it causes functional and structural damage to the arterial wall, leading to stiffness. Several studies have related oxidative stress, production of free radicals, and neuroendocrine and genetic changes to the physiopathogenesis of vascular aging. Indirect ways to analyze that aging process have been widely studied, pulse wave velocity (PWV being considered gold standard to assess arterial stiffness, because there is large epidemiological evidence of its predictive value for cardiovascular events, and it requires little technical knowledge to be performed. A pulse wave is generated during each cardiac contraction and travels along the arterial bed until finding peripheral resistance or any bifurcation point, determining the appearance of a reflected wave. In young individuals, arteries tend to be more elastic, therefore, the reflected wave occurs later in the cardiac cycle, reaching the heart during diastole. In older individuals, however, the reflected wave occurs earlier, reaching the heart during systole. Because PWV is an important biomarker of vascular damage, highly valuable in determining the patient’s global cardiovascular risk, we chose to review the articles on vascular aging in the context of cardiovascular risk factors and the tools available to the early identification of that damage.

  5. Carotid stiffness is associated with impairment of cognitive performance in individuals with and without type 2 diabetes. The Maastricht Study.

    Science.gov (United States)

    Geijselaers, Stefan L C; Sep, Simone J S; Schram, Miranda T; van Boxtel, Martin P J; van Sloten, Thomas T; Henry, Ronald M A; Reesink, Koen D; Kroon, Abraham A; Koster, Annemarie; Schaper, Nicolaas C; Dagnelie, Pieter C; van der Kallen, Carla J H; Biessels, Geert Jan; Stehouwer, Coen D A

    2016-10-01

    There is increasing evidence linking arterial (mainly aortic) stiffness and type 2 diabetes, a risk factor for arterial stiffness, to cognitive impairment and dementia. However, data on carotid stiffness, which may be especially relevant for cognitive performance, are scarce, and few studies have addressed the interplay between arterial stiffness, type 2 diabetes, and cognitive performance. We studied individuals with (n = 197) and without (n = 528) type 2 diabetes, who completed a neuropsychological test battery and underwent applanation tonometry and vascular ultrasound to evaluate aortic (i.e. carotid-to-femoral pulse wave velocity) and carotid stiffness (i.e. distensibility, compliance and Young's elastic modulus). Linear regression analyses were performed and adjusted for demographics, vascular risk factors, and depression. Overall, our results showed that carotid, but not aortic, stiffness was associated with worse cognitive performance, primarily in the domains of processing speed (standardized regression coefficient for distensibility -0.083, p = 0.040; compliance -0.077, p = 0.032) and executive function and attention (distensibility -0.133, p = 0.001; compliance -0.090, p = 0.015; Young's elastic modulus -0.081, p = 0.027). These associations did not differ by diabetes status. The differences in cognitive performance between individuals with and without type 2 diabetes (mean difference in domain scores relative to those without diabetes for free recall memory -0.23, processing speed -0.19, executive function and attention -0.23; all p ≤ 0.009 and adjusted for demographics, traditional vascular risk factors, and depression) were not substantially altered after additional adjustment for carotid stiffness. Our findings suggest that carotid stiffness is associated with cognitive performance in both individuals with and without diabetes, but does not mediate the relationship between type 2 diabetes and cognitive dysfunction. Copyright

  6. Gradual stiffness versus magnetic imaging-guided variable stiffness colonoscopes: A randomized noninferiority trial.

    Science.gov (United States)

    Garborg, Kjetil; Wiig, Håvard; Hasund, Audun; Matre, Jon; Holme, Øyvind; Noraberg, Geir; Løberg, Magnus; Kalager, Mette; Adami, Hans-Olov; Bretthauer, Michael

    2017-02-01

    Colonoscopes with gradual stiffness have recently been developed to enhance cecal intubation. We aimed to determine if the performance of gradual stiffness colonoscopes is noninferior to that of magnetic endoscopic imaging (MEI)-guided variable stiffness colonoscopes. Consecutive patients were randomized to screening colonoscopy with Fujifilm gradual stiffness or Olympus MEI-guided variable stiffness colonoscopes. The primary endpoint was cecal intubation rate (noninferiority limit 5%). Secondary endpoints included cecal intubation time. We estimated absolute risk differences with 95% confidence intervals (CIs). We enrolled 475 patients: 222 randomized to the gradual stiffness instrument, and 253 to the MEI-guided variable stiffness instrument. Cecal intubation rate was 91.7% in the gradual stiffness group versus 95.6% in the variable stiffness group. The adjusted absolute risk for cecal intubation failure was 4.3% higher in the gradual stiffness group than in the variable stiffness group (upper CI border 8.1%). Median cecal intubation time was 13 minutes in the gradual stiffness group and 10 minutes in the variable stiffness group (p < 0.001). The study is inconclusive with regard to noninferiority because the 95% CI for the difference in cecal intubation rate between the groups crosses the noninferiority margin. (ClinicalTrials.gov identifier: NCT01895504).

  7. Research on Detection of Machine Stiffness

    OpenAIRE

    Wang Li-Jie; Shi Wei-Chao; Xu De-Kai

    2015-01-01

    Machine tool stiffness is a principal factor affecting machine tool precision, traditional methods can only be used to detect limited categories of machine tools. The paper introduces a new scheme to detect machine tool stiffness on the basis of dynamic detection of machine tool stiffness considering its characteristics and stress state during processing. An experiment conducted in turn-milling machining center CH7516GS indicated by comparison that statics analysis of finite elements matched ...

  8. Tobacco smoking and aortic aneurysm

    DEFF Research Database (Denmark)

    Sode, Birgitte F; Nordestgaard, Børge G; Grønbæk, Morten

    2012-01-01

    BACKGROUND: We determined the predictive power of tobacco smoking on aortic aneurysm as opposed to other risk factors in the general population. METHODS: We recorded tobacco smoking and other risk factors at baseline, and assessed hospitalization and death from aortic aneurysm in 15,072 individuals...... aneurysm in males and females consuming above 20g tobacco daily was 3.5% and 1.3%, among those >60years with plasma cholesterol >5mmol/L and a systolic blood pressure >140mmHg. CONCLUSIONS: Tobacco smoking is the most important predictor of future aortic aneurysm outcomes in the general population...

  9. Measurement and Treatment of Passive Muscle Stiffness

    DEFF Research Database (Denmark)

    Kirk, Henrik

    This PhD thesis is based on research conducted at the University of Copenhagen and Helene Elsass Center from 2012 to 2015. Measurements and treatment of passive muscle stiffness in people with cerebral palsy (CP) comprise the focus of the thesis. The thesis summarizes the results from four studies...... stiffness. I introduce how to evaluate and distinguish between passive muscle stiffness and reflex-mediated stiffness in research and in clinical practice. Furthermore, I present ”the Portable Spasticity Assessment Device”, which was developed as a part of the PhD study. I discuss the validity...

  10. A new approach to determine press stiffness

    DEFF Research Database (Denmark)

    Arentoft, Mogens; Wanheim, Tarras

    2004-01-01

    A new procedure is proposed for measuring press stiffness, including separated horizontal and vertical loading of the press frame. The load can be eccentrically positioned for measuring rotational stiffnesses. Two loading devices and corresponding measuring equipment for registration of press...... deflections are designed. The press stiffness is presented as a 6 by 6 flexibility matrix. The approach has been tested by measuring the stiffness of a 5000 kN O-frame, ring element, hydraulic press, a 10000 kN O-frame, pillar element, hydraulic press and a 10000 kN O-frame, ring element mechanical press...

  11. Abnormal pulmonary artery stiffness in pulmonary arterial hypertension: in vivo study with intravascular ultrasound.

    Directory of Open Access Journals (Sweden)

    Edmund M T Lau

    Full Text Available BACKGROUND: There is increasing recognition that pulmonary artery stiffness is an important determinant of right ventricular (RV afterload in pulmonary arterial hypertension (PAH. We used intravascular ultrasound (IVUS to evaluate the mechanical properties of the elastic pulmonary arteries (PA in subjects with PAH, and assessed the effects of PAH-specific therapy on indices of arterial stiffness. METHOD: Using IVUS and simultaneous right heart catheterisation, 20 pulmonary segments in 8 PAH subjects and 12 pulmonary segments in 8 controls were studied to determine their compliance, distensibility, elastic modulus and stiffness index β. PAH subjects underwent repeat IVUS examinations after 6-months of bosentan therapy. RESULTS: AT BASELINE, PAH SUBJECTS DEMONSTRATED GREATER STIFFNESS IN ALL MEASURED INDICES COMPARED TO CONTROLS: compliance (1.50±0.11×10(-2 mm(2/mmHg vs 4.49±0.43×10(-2 mm(2/mmHg, p<0.0001, distensibility (0.32±0.03%/mmHg vs 1.18±0.13%/mmHg, p<0.0001, elastic modulus (720±64 mmHg vs 198±19 mmHg, p<0.0001, and stiffness index β (15.0±1.4 vs 11.0±0.7, p = 0.046. Strong inverse exponential associations existed between mean pulmonary artery pressure and compliance (r(2 = 0.82, p<0.0001, and also between mean PAP and distensibility (r(2 = 0.79, p = 0.002. Bosentan therapy, for 6-months, was not associated with any significant changes in all indices of PA stiffness. CONCLUSION: Increased stiffness occurs in the proximal elastic PA in patients with PAH and contributes to the pathogenesis RV failure. Bosentan therapy may not be effective at improving PA stiffness.

  12. Ruptured Abdominal Aortic Aneurysm

    Directory of Open Access Journals (Sweden)

    Jessica Andrusaitis

    2017-07-01

    Full Text Available History of present illness: A 69-year-old male with poorly controlled hypertension presented with 1 hour of severe low back pain that radiated to his abdomen. The patient was tachycardic and had an initial blood pressure of 70/40. He had a rigid and severely tender abdomen. The patient’s history of hypertension, abnormal vital signs, severity and location of his pain were suspicious for a ruptured abdominal aortic aneurysm (AAA. Therefore, a computed tomography angiogram (CTA was ordered. Significant findings: CTA demonstrated a ruptured 7.4 cm infrarenal abdominal aortic aneurysm with a large left retroperitoneal hematoma. Discussion: True abdominal aortic aneurysm is defined as at least a 3cm dilatation of all three layers of the arterial wall of the abdominal aorta.1 An estimated 15,000 people die per year in the US of this condition.2 Risk factors for AAA include males older than 65, tobacco use, and hypertension.1,3,4 There are also congenital, mechanical, traumatic, inflammatory, and infectious causes of AAA.3 Rupture is often the first manifestation of the disease. The classic triad of abdominal pain, pulsatile mass, and hypotension is seen in only 50% of ruptured AAAs.5 Pain (abdominal, groin, or back is the most common symptom. The most common misdiagnoses of ruptured AAAs are renal colic, diverticulitis, and gastrointestinal hemorrhage.6 Bedside ultrasonography is the fastest way to detect this condition and is nearly 100% sensitive.1 One study showed that bedside ultrasounds performed by emergency physicians had a sensitivity of .94 [95% CI = .86-1.0] and specificity of 1 [95% CI = .98-1.0] for detecting AAAs.7 CTA has excellent sensitivity (approximately 100% and yields the added benefit of facilitating surgical planning and management.1 Without surgical treatment, a ruptured AAA is almost uniformly fatal, and 50% of those who undergo surgery do not survive.1 Early resuscitation and coordination with vascular surgery should be

  13. Bicuspid Aortic Valve and Aortic Root Morphology in Hispanic Patients.

    Science.gov (United States)

    Horvath, Sofia A; Mihos, Christos G; Rodriguez-Escudero, Juan P; Elmahdy, Hany M; Pineda, Andres M; Rosen, Gerald P; Carlos Brenes, Juan; Santana, Orlando

    2015-11-01

    The study aim was to evaluate the aortic valve and aortic root morphology in Hispanic patients with a bicuspid aortic valve (BAV). BAV disease is one of the most common congenital anomaly of the heart, and is associated with abnormalities of the aorta. Interracial differences have been described between Caucasian and African-American patients with BAV, which may have clinical and therapeutic implications. The clinical and anatomical spectrum of BAV disease in Hispanic patients has not been well established. A retrospective review was conducted of all heart operations performed at the authors' institution between April 2008 and June 2013. Patients with BAV who underwent aortic valve replacement (AVR) were identified. All echocardiograms available were reviewed in order to compare cusp morphology, valvular function, and ascending aorta dimensions between Hispanic and non-Hispanic individuals. A total of 291 patients (159 Hispanic, 132 non-Hispanic) with a mean age of 62 ± 13 years were identified. The baseline characteristics were similar between the two groups. In both Hispanics and non-Hispanics, the most prevalent cusp morphology was fusion of the right and left coronary cusps (82% for both groups). The most common indication for surgery was aortic stenosis. Hispanic patients had a larger aortic annulus diameter (2.58 ± 0.32 cm versus 2.39 ± 0.39 cm, p = 0.04). However, this difference was not significant after adjusting for age, gender, body surface area, and the presence of moderate-to-severe aortic insufficiency. Ascending aortopathy was present in 42.7% of the total study population. Regardless of ethnicity, the most common pattern of aortopathy involved the tubular ascending aorta with mild to moderate root enlargement (type 1). Compared with other ethnic groups, Hispanics with BAVs have similar aortic valve morphology and function, as well as comparable aortopathy.

  14. [Aortic root dilatation rate in pediatric patients with Marfan syndrome treated with losartan].

    Science.gov (United States)

    Mariucci, Elisabetta; Guidarini, Marta; Donti, Andrea; Lovato, Luigi; Wischmeijer, Anita; Angeli, Emanuela; Gargiulo, Gaetano D; Picchio, Fernando M; Bonvicini, Marco

    2015-12-01

    Medical therapy with angiotensin II receptor blockers/angiotensin-converting enzyme inhibitors and/or beta-blockers was reported to reduce aortic root dilatation rates in pediatric patients with Marfan syndrome. No data are available in the literature on losartan effects after 3 years of therapy. The aim of our study was to establish whether losartan reduces aortic root dilatation rates in pediatric patients with Marfan syndrome in the mid and long term. This is a retrospective analysis of 38 pediatric patients with Marfan syndrome followed at the Marfan Clinic of S. Orsola-Malpighi Hospital of the University of Bologna (Italy). Aortic diameters were measured at sinuses of Valsalva and proximal ascending aorta with transthoracic echocardiography. After a mean follow-up of 4.5 ± 2.5 years (range 2-9 years), aortic root z score at sinuses of Valsalva and proximal ascending aorta remained stable. The average annual rate of change in aortic root z score was -0.1 ± 0.4 and 0 ± 0.3 at sinuses of Valsalva and proximal ascending aorta, respectively. The mean dose of losartan was 0.7 ± 0.3 mg/kg/day. Three patients were non-responders, probably because of late beginning or low dose of therapy. Eight patients underwent cardiac surgery (aortic root surgery in 5 and mitral valve repair in 3), all of them started losartan later in life. Despite the retrospective design of the study and the small sample size, a beneficial effect of losartan therapy was observed in pediatric patients with Marfan syndrome in the mid and long term. Late beginning or low doses of losartan can turn off the effects of therapy.

  15. Proximal femoral fractures

    DEFF Research Database (Denmark)

    Palm, Henrik; Teixidor, Jordi

    2015-01-01

    -displaced femoral neck fractures and prosthesis for displaced among the elderly; and sliding hip screw for stabile- and intramedullary nails for unstable- and sub-trochanteric fractures) but they are based on a variety of criteria and definitions - and often leave wide space for the individual surgeons' subjective...... guidelines for hip fracture surgery and discuss a method for future pathway/guideline implementation and evaluation. METHODS: By a PubMed search in March 2015 six studies of surgical treatment pathways covering all types of proximal femoral fractures with publication after 1995 were identified. Also we...... searched the homepages of the national heath authorities and national orthopedic societies in West Europe and found 11 national or regional (in case of no national) guidelines including any type of proximal femoral fracture surgery. RESULTS: Pathway consensus is outspread (internal fixation for un...

  16. Proximal humeral fractures

    OpenAIRE

    Mauro, Craig S.

    2011-01-01

    Proximal humeral fractures may present with many different configurations in patients with varying co-morbities and expectations. As a result, the treating physician must understand the fracture pattern, the quality of the bone, other patient-related factors, and the expanding range of reconstructive options to achieve the best functional outcome and to minimize complications. Current treatment options range from non-operative treatment with physical therapy to fracture fixation using percuta...

  17. Type A aortic dissection: Are there CT signs suggestive of valvular involvement?

    Science.gov (United States)

    Platon, Alexandra; Bernard, Stephane; Perrin, Nils; Murith, Nicolas; John, Gregor; Perneger, Thomas; Rutschmann, Olivier T; Poletti, Pierre-Alexandre

    2016-11-01

    To identify the predictive signs of aortic valve involvement on the non-electrocardiogram (ECG)-gated admission computed tomography (CT) of patients with Type A aortic dissection (AD) according to the Stanford classification. We retrospectively analyzed the non-ECG-gated CT examinations of patients admitted to the emergency department who underwent surgery for Type A AD over a period of 4 years. The diameter of the following structures was calculated as the mean of the smallest and largest diameters (mm) measured in two different planes: aortic annulus, sinus of Valsalva, sinotubular junction, and proximal ascending aorta. These parameters were compared against operative reports in order to determine whether they were predictive of aortic valve involvement. In total, 20 patients (13 men and 7 women) of a mean age of 59.5 years (29-80) were included, 55% of patients (11/20) having surgically proven valvular involvement. The mean diameters (inmm) of the aortic annulus, sinus of Valsalva, sinotubular junction and proximal ascending aorta in the group with (and without, respectively) valvular involvement was 27.7 (26.7), 44.3 (38.1), 42.6 (36.6), and 47.8 (45.9). Only the measurement of the mean diameter of the sinuses of Valsalva was significantly predictive (p=0.02) of aortic valve involvement. Our findings suggest that measuring the diameter of the sinuses of Valsalva on non-ECG-gated admission CT examinations allows for predicting aortic valve involvement in Type A AD patients. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  18. Abdominal aortic aneurysms

    DEFF Research Database (Denmark)

    Lindholt, Jes Sanddal

    2010-01-01

    Although the number of elective operations for abdominal aortic aneurysms (AAA) is increasing, the sex- and age-standardised mortality rate of AAAs continues to rise, especially among men aged 65 years or more. The lethality of ruptured AAA continues to be 80-95%, compared with 5-7% by elective...... surgery of symptomfree AAA. In order to fulfil all WHO, European, and Danish criteria for screening, a randomised hospitalbased screening trial of 12,639 65-73 year old men in Viborg County (Denmark) was initiated in 1994. It seemed that US screening is a valid, suitable and acceptable method of screening...... intervals. Two large RCTs have given clear indications of operation. Survivors of surgery enjoy the same quality of life as the background population, and only 2-5% of patients refuse an offer of surgery. Early detection seems relevant since the cardiovascular mortality is more than 4 times higher in AAA...

  19. Hybrid Completion of Aortic Repair after Type A Aortic Dissection in a Patient with Marfan's Syndrome.

    Science.gov (United States)

    Russell, Terri-Ann Teisha; Yeh, James Shue-Min; Kourliouros, Antonios; Nienaber, Christoph A

    2017-01-01

    Medicine and engineering are in collaboration to assist in the tackling of daunting surgical techniques which are associated with high rates of morbidity and mortality, in exchange for minimally invasive approaches with lower procedural risk. Endovascular procedures in general have already reduced the risk of surgery by limiting the extent of open surgery and often replacing it with purely percutaneous or hybrid procedures. Here, we describe a patient who had complex staged surgery with open repair of a proximal portion of a type A aortic dissection followed by a staged endovascular reconstruction of the arch and descending aorta by means of a fenestrated stent-graft to secure the left subclavian artery and the posterior cerebral circulation.

  20. The mechanical benefit of medial support screws in locking plating of proximal humerus fractures.

    Directory of Open Access Journals (Sweden)

    Wen Zhang

    Full Text Available BACKGROUND: The purpose of this study was to evaluate the biomechanical advantages of medial support screws (MSSs in the locking proximal humeral plate for treating proximal humerus fractures. METHODS: Thirty synthetic left humeri were randomly divided into 3 subgroups to establish two-part surgical neck fracture models of proximal humerus. All fractures were fixed with a locking proximal humerus plate. Group A was fixed with medial cortical support and no MSSs; Group B was fixed with 3 MSSs but without medial cortical support; Group C was fixed with neither medial cortical support nor MSSs. Axial compression, torsional stiffness, shear stiffness, and failure tests were performed. RESULTS: Constructs with medial support from cortical bone showed statistically higher axial and shear stiffness than other subgroups examined (P<0.0001. When the proximal humerus was not supported by medial cortical bone, locking plating with medial support screws exhibited higher axial and torsional stiffness than locking plating without medial support screws (P ≤ 0.0207. Specimens with medial cortical bone failed primarily by fracture of the humeral shaft or humeral head. Specimens without medial cortical bone support failed primarily by significant plate bending at the fracture site followed by humeral head collapse or humeral head fracture. CONCLUSIONS: Anatomic reduction with medial cortical support was the stiffest construct after a simulated two-part fracture. Significant biomechanical benefits of MSSs in locking plating of proximal humerus fractures were identified. The reconstruction of the medial column support for proximal humerus fractures helps to enhance mechanical stability of the humeral head and prevent implant failure.

  1. The Effect of an Angiotensin Receptor Blocker on Arterial Stiffness in Type 2 Diabetes Mellitus Patients with Hypertension

    Directory of Open Access Journals (Sweden)

    Ji Hyun Kim

    2011-06-01

    Full Text Available BackgroundHypertension and type 2 diabetes mellitus are major risk factors for cardiovascular disease. This study analyzed the changes in central aortic waveforms and pulse wave velocity as well as related parameters after treatment with valsartan, an angiotensin II type 1 receptor blocker, in patients with type 2 diabetes and hypertension.MethodsWe used pulse wave analysis to measure central aortic waveform in a total of 98 subjects. In 47 of these patients, pulse wave velocity measurements were obtained before and after 12 weeks of treatment with valsartan.ResultsIn the central aortic waveform analysis, the aortic pulse pressure and augmentation index were significantly decreased after valsartan treatment, as was the aortic pulse wave velocity. Factors contributing to the improvement in pulse wave velocity were the fasting blood glucose and haemoglobin A1c levels.ConclusionShort-term treatment with valsartan improves arterial stiffness in patients with type 2 diabetes and hypertension, and the glucose status at baseline was associated with this effect.

  2. Acute Aortic Dissection Mimicking STEMI in the Catheterization Laboratory: Early Recognition Is Mandatory

    Directory of Open Access Journals (Sweden)

    Alessio Arrivi

    2012-01-01

    Full Text Available Coronary malperfusion due to type A aortic dissection is a life-threatening condition where timely recognition and treatment are mandatory. A 77-year-old woman underwent an acute evolving type A aortic dissection mimicking acute myocardial infarction. Two pathophysiologic mechanisms are discussed: either thrombosis migrating from a previously treated giant aneurism of proximal left anterior descending or a local arterial complication due to left main stenting. Recognition of these occurrences in the catheterization laboratory is important to look immediately for surgery.

  3. Load to Failure and Stiffness

    Science.gov (United States)

    Esquivel, Amanda O.; Duncan, Douglas D.; Dobrasevic, Nikola; Marsh, Stephanie M.; Lemos, Stephen E.

    2015-01-01

    Background: Rotator cuff tendinopathy is a frequent cause of shoulder pain that can lead to decreased strength and range of motion. Failures after using the single-row technique of rotator cuff repair have led to the development of the double-row technique, which is said to allow for more anatomical restoration of the footprint. Purpose: To compare 5 different types of suture patterns while maintaining equality in number of anchors. The hypothesis was that the Mason-Allen–crossed cruciform transosseous-equivalent technique is superior to other suture configurations while maintaining equality in suture limbs and anchors. Study Design: Controlled laboratory study. Methods: A total of 25 fresh-frozen cadaveric shoulders were randomized into 5 suture configuration groups: single-row repair with simple stitch technique; single-row repair with modified Mason-Allen technique; double-row Mason-Allen technique; double-row cross-bridge technique; and double-row suture bridge technique. Load and displacement were recorded at 100 Hz until failure. Stiffness and bone mineral density were also measured. Results: There was no significant difference in peak load at failure, stiffness, maximum displacement at failure, or mean bone mineral density among the 5 suture configuration groups (P sutures in the repair should be considered to judge the strength of the repair. Clinical Relevance: Previous in vitro studies have shown the double-row rotator cuff repair to be superior to the single-row repair; however, clinical research does not necessarily support this. This study found no difference when comparing 5 different repair methods, supporting research that suggests the number of sutures and not the pattern can affect biomechanical properties. PMID:26665053

  4. Variations of the aortic arch - a study on the most common branching patterns

    Energy Technology Data Exchange (ETDEWEB)

    Muller, Marguerite; Schmitz, Bernd L; Schick, Melanie; Schloetzer, Wiebke (Dept. of Diagnostic and Interventional Radiology, Section Neuroradiology, Univ. Ulm (Germany)), email: marguerite.mueller@uni-ulm.de; Pauls, Sandra (Dept. of Diagnostic and Interventional Radiology, Univ. Ulm (Germany)); Roehrer, Stefan; Kapapa, Thomas (Dept. of Neurosurgery, Univ. Ulm (Germany))

    2011-09-15

    Background: Anatomical variants of the aortic arch and its branching patterns often appear as an incidental finding during routine computed tomography (CT) scanning. These variations can be of relevance when performing angiography or endovascular interventions and may cause symptoms such as dysphagia. Purpose: To analyze common anatomical variations found within the arteries originating from the aortic arch in patients using contrast CT imaging techniques. Material and Methods: A total of 2033 contrast CT scans were analyzed. To obtain a truly representative sample, cases were chosen from different hospital departments without previous knowledge of the patient history. Results: The total percentage of variations within the analyzed patients was 13.3%. In 8.0% a truncus bicaroticus was found. 4.2% of the patients showed a left vertebral artery originating directly from the aortic arch, mostly proximal, and in 1 case distal to the left subclavian artery. In 1.0% we found an aberrant right subclavian artery. We also found a single case of a right descending aortic arch. Conclusion: Variations of the aortic arch and its branching are frequently found, mostly as an incidental finding during routine diagnostic scanning. A contrast-enhanced CT scan is a good method with which to study the aortic arch and its associated branching pattern

  5. Management of acute aortic syndrome.

    Science.gov (United States)

    Clough, Rachel E; Nienaber, Christoph A

    2015-02-01

    Acute aortic syndrome (AAS) encompasses a group of severe, life-threatening disorders of the aorta, including acute aortic dissection, intramural haematoma (IMH), and penetrating aortic ulcer (PAU). The concept of AAS was developed to enable the early identification and definitive treatment of patients with chest pain from an aortic origin. Aortic dissection is the most common form of AAS, followed by IMH and PAU. Congenital cardiovascular defects, genetic syndromes, and nonsyndromic genetic variants have all been linked with the development of AAS. The diagnosis of AAS in the clinic can be made using imaging modalities such as CT, echocardiography, and MRI. The initial management of patients with AAS is focussed on the control of blood pressure to reduce aortic wall stress. A multidisciplinary team is required to assess each patient and decide whether endovascular or open surgical treatment, or further medical management is indicated. The optimal treatment of patients with AAS remains a challenging clinical dilemma, and further studies are required to fully characterize conditions within the AAS spectrum and to design individualized, patient-centred treatment plans.

  6. Curvature dependent modulation of fish fin stiffness

    Science.gov (United States)

    Nguyen, Khoi; Yu, Ning; Bandi, Mahesh; Venkadesan, Madhusudhan; Mandre, Shreyas

    Propulsion and maneuvering ability of fishes depends on the stiffness of their fins. However, increasing stiffness by simply adding material to thicken the fin would incur a substantial energetic cost associated with flapping the fin. We propose that fishes increase stiffness of the fin not by building thicker fins, but by geometrically coupling out-of-plane bending of the fin's rays with in-plane stretching of a stiff membrane that connects the rays. We present a model of fin elasticity for ray-finned fish, where we decompose the fin into a series of elastic beams (rays) with springy interconnections (membrane). In one limit, where the membranes are infinitely extensible, the fin's stiffness is no more than the sum of the stiffness of individual rays. At the other limit of an inextensible membrane, fin stiffness reaches an asymptotic maximum. The asymptote value increases monotonically with curvature. We propose that musculature at the base of the fin controls fin curvature, and thereby modulates stiffness.

  7. Embodying Desired Behavior in Variable Stiffness Actuators

    NARCIS (Netherlands)

    Visser, L.C.; Stramigioli, Stefano; Bicchi, Antonio

    2011-01-01

    Variable stiffness actuators are a class of actuators with the capability of changing their apparent output stiffness independently from the actuator output position. This is achieved by introducing internally a number of compliant elements, and internal actuated degrees of freedom that determine

  8. Stiffness and damping in mechanical design

    National Research Council Canada - National Science Library

    Rivin, Eugene I

    1999-01-01

    ... important conceptual issues are stiffness of mechanical structures and their components and damping in mechanical systems sensitive to and/or generating vibrations. Stiffness and strength are the most important criteria for many mechanical designs. However, although there are hundreds of books on various aspects of strength, and strength issues ar...

  9. Multimorbidity in Older Adults with Aortic Stenosis.

    Science.gov (United States)

    Lindman, Brian R; Patel, Jay N

    2016-05-01

    Aortic stenosis is a disease of older adults; many have associated comorbidities. With the aging of the population and the emergence of transcatheter aortic valve replacement as a treatment, clinicians will increasingly be confronted with aortic stenosis and multimorbidity, making the evaluation, management, and treatment of aortic stenosis more complex. To optimize patient-centered clinical outcomes, new treatment paradigms are needed that recognize the import and influence of multimorbidity on patients with aortic stenosis. The authors review the prevalence of medical and aging-related comorbidities in patients with aortic stenosis, their impact on outcomes, and discuss how they influence management and treatment decisions. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Concepts to optimize stent-grafting of abdominal aortic aneurysms based on results of experimental studies; Konzepte zur Optimierung der Stentgraftversorgung von Bauchaortenaneurysmen auf der Basis tierexperimenteller Ergebnisse

    Energy Technology Data Exchange (ETDEWEB)

    Chavan, A.; Kirchhoff, T.; Baus, S.; Galanski, M. [Medizinische Hochschule Hannover (Germany). Abt. Diagnostische Radiologie 1; Pichlmaier, M. [Medizinische Hochschule Hannover (Germany). Leibniz Forschungslab. fuer Biotechnologie und Kuenstliche Organe an der Klinik fuer Thorax-, Herz- und Gefaesschirurgie

    2001-08-01

    Purpose. In the endoluminal therapy of abdominal aortic aneurysms, a short proximal aneurysm neck, endoleaks and the large size and stiffness of the introducer systems are responsible for many of the complications and sub-optimal outcomes. The purpose of the present review article is to to suggest strategies to minimize these complications based on the results of experimental studies in animals. Material and methods. After implanting various types of stents across the renal artery origins, the functional and morphological changes in the kidneys and renal vessels were studied by various authors. In order to prevent progressive widening of the proximal aneurysmal neck and graft dislocation, Sonesson et al. performed a laparoscopic banding around the proximal neck in pigs. To study the effects of endoleaks, Marty, Schurink and Pitton carried out pressure measurements in experimental aneurysms with and without endoleaks. Sakaguchi and Pavcnik developed the 'Twin-tube endografts' (TTEG) and the 'Bifurcated drum occluder endografts' (BDOEG) and tested them in dogs. Results. Up to 3 months after suprarenal stent placement, Chavan et al. detected no significant fall in the mean inulin clearance in sheep (140{+-}46 ml/min before, 137{+-}58 ml/min after). Nasim et al. and Malina et al. reported similar observations with respect to renal function. Suprarenal fixation may result in isolated thrombotic occlusions of the renal arteries and microinfarcts in the kidneys. Mean aortic diameters at the level of banding were significantly smaller in the animals with aortic banding as opposed to those in the control group without banding (8 mm vs 11 mm, p=0.004). The banding caused a secure proximal fixation of the stent-graft. Persistent endoleaks resulted in significantly higher intraaneurysmal pressures. Although the TTEG and the BDOEG stent-grafts required smaller sheaths, occlusions were observed in 8% (TTEG) and 60% (BDOEG) of the graft limbs. (orig.) [German

  11. [Spiral CT and MRT of the operated Stanford-type-A aortic dissection: its course and complications].

    Science.gov (United States)

    Sommer, T; Abu-Ramadan, D; Pauleit, D; Hofer, U; Likungu, J; Preusse, K; Layer, G; Schild, H

    1998-02-01

    To demonstrate normal postoperative spiral CT and MRI findings and typical complications in patients with aortic repair after Stanford type A aortic dissection. 24 patients with aortic repair after Stanford type A aortic dissection were followed up by spiral CT and MRI (0.5 Tesla). Presence of persistent dissection, progressive or new dissection, proximal and distal anastomosis, periprosthetic space, supraaortic vessels, thrombosis and dilatation of the true and false lumen were evaluated. The following postoperative complications were seen: three pseudoaneurysms which developed at the proximal anastomoses of the Dacron prosthesis in two cases and at the insertion site of the reimplanted left coronary artery after implantation of a composite graft (Bentall procedure) in one case; one re-dissection; one perforation of the false lumen; periprosthetic flow in one patient after surgical repair of type A dissection by the graft inclusion technique; progressive dilatation of the false lumen in 4 cases; dilatation of the aortic root in a Marfan patient after replacement of the ascending aorta. Precise knowledge of the surgical technique performed is crucial to accurate postoperative imaging evaluation. MRI is the method of choice in the postoperative follow-up of clinically stable patients with aortic dissections.

  12. Foil Bearing Stiffness Estimation with Pseudospectral Scheme

    Directory of Open Access Journals (Sweden)

    Sankar Balaji

    2016-01-01

    Full Text Available Compliant foil gas lubricated bearings are used for the support of light loads in the order of few kilograms at high speeds, in the order of 50,000 RPM. The stiffness of the foil bearings depends both on the stiffness of the compliant foil and on the lubricating gas film. The stiffness of the bearings plays a crucial role in the stable operation of the supported rotor over a range of speeds. This paper describes a numerical approach to estimate the stiffness of the bearings using pseudo spectral scheme. Methodology to obtain the stiffness of the foil bearing as a function of weight of the shaft is given and the results are presented.

  13. Stiffness Control of Surgical Continuum Manipulators.

    Science.gov (United States)

    Mahvash, Mohsen; Dupont, Pierre E

    2011-04-01

    This paper introduces the first stiffness controller for continuum robots. The control law is based on an accurate approximation of a continuum robot's coupled kinematic and static force model. To implement a desired tip stiffness, the controller drives the actuators to positions corresponding to a deflected robot configuration that produces the required tip force for the measured tip position. This approach provides several important advantages. First, it enables the use of robot deflection sensing as a means to both sense and control tip forces. Second, it enables stiffness control to be implemented by modification of existing continuum robot position controllers. The proposed controller is demonstrated experimentally in the context of a concentric tube robot. Results show that the stiffness controller achieves the desired stiffness in steady state, provides good dynamic performance, and exhibits stability during contact transitions.

  14. Determination of 6 stiffnesses for a press

    DEFF Research Database (Denmark)

    Arentoft, Mogens; Eriksen, Morten; Wanheim, Tarras

    2000-01-01

    the workpiece will result in deflections of the press, which will decrease the tolerances of the component. At present, it is possible to measure the reaction forces from the workpiece, for instance by use of the model material technique as described in [1-2]. If the stiffness and clearances of the press...... is known too, the final dimensions can be predicted by divide the force by the stiffness and add the clearance. If the stiffness of the press is known, it is possible to optimize the orientation of the workpiece too, so the direction, in which the best tolerances is demanded, is equal to the direction...... in which the press has the highest stiffness. Furthermore, knowledge about the stiffnesses of all presses in a production system makes it possible to choose the press which best fit to a specific process....

  15. Reducing the Inconsistency between Doppler and Invasive Measurements of the Severity of Aortic Stenosis Using Aortic Valve Coefficient: A Retrospective Study on Humans

    Directory of Open Access Journals (Sweden)

    Anup K. Paul

    2014-01-01

    Full Text Available Background. It is not uncommon to observe inconsistencies in the diagnostic parameters derived from Doppler and catheterization measurements for assessing the severity of aortic stenosis (AS which can result in suboptimal clinical decisions. In this pilot study, we investigate the possibility of improving the concordance between Doppler and catheter assessment of AS severity using the functional diagnostic parameter called aortic valve coefficient (AVC, defined as the ratio of the transvalvular pressure drop to the proximal dynamic pressure. Method and Results. AVC was calculated using diagnostic parameters obtained from retrospective chart reviews. AVC values were calculated independently from cardiac catheterization (AVCcatheter and Doppler measurements (AVCdoppler. An improved significant correlation was observed between Doppler and catheter derived AVC (r=0.92, P<0.05 when compared to the correlation between Doppler and catheter measurements of mean pressure gradient (r=0.72, P<0.05 and aortic valve area (r=0.64, P<0.05. The correlation between Doppler and catheter derived AVC exhibited a marginal improvement over the correlation between Doppler and catheter derived aortic valve resistance (r=0.89, P<0.05. Conclusion. AVC is a refined clinical parameter that can improve the concordance between the noninvasive and invasive measures of the severity of aortic stenosis.

  16. Morphological Evaluation of Proximal Anastomosis by PAS-Port(®) System in Patients with Long-Term Patent Grafts.

    Science.gov (United States)

    Kawasaki, Muneyasu; Fujii, Takeshiro; Hara, Masanori; Sasaki, Yuki; Katayanagi, Tomoyuki; Okuma, Shinnosuke; Watanabe, Yoshinori

    2015-01-01

    We examined grafts employing for morphological analysis of early and long-term results on proximal anastomosis with the PAS-Port(®). One hundred and four patients treated by OPCAB with PAS-Port(®) were performed postoperative MDCT. Morphological evaluation of the proximal anastomotic region was classified into three groups (A; graft was anastomosed almost perpendicularly to the aortic wall, B; graft was same type A, but subsequently curved to form an acute angle with the aortic wall, C; graft take off acute angle with the aortic wall) evaluated on planar and sagittal sections. One hundred twenty-six PAS-Port(®) were used. Patency rate was 99.0% at discharge, 94.7% at 1 year, and no blockages were detected thereafter in patients examined. The morphology rate was A 50.6%, B 15.3% and C 34.1% on planar sections, and A 58.8%, B 10.6% and C 30.6% on sagittal sections. The morphological evaluation of grafts revealed the degree of freedom in graft design to be relatively high and long-term patency posed no particular problem even if the layout of the proximal anastomotic region involved a relatively acute angle. The PAS-Port(®) was considered to be a highly reliable device which performed appropriate proximal anastomosis and improved the patency of vein grafting to the aortic wall.

  17. Endoluminal treatment of aortic dissection

    Energy Technology Data Exchange (ETDEWEB)

    Chavan, Ajay; Lotz, Joachim; Galanski, Michael [Department of Diagnostic Radiology, Hannover Medical School, Carl Neuberg Strasse 1, 30625, Hannover (Germany); Oelert, Frank; Haverich, Axel; Karck, Matthias [Department of Thoracic and Cardiovascular Surgery, Hannover Medical School, Carl Neuberg Strasse 1, 30625, Hannover (Germany)

    2003-11-01

    Aortic dissection is most often a catastrophic medical emergency which, if untreated, can be potentially fatal. The intention of therapy in patients with aortic dissection is to prevent aortic rupture or aneurysm formation as well as to relieve branch vessel ischaemia. Patients with aortic dissection are often poor candidates for anaesthesia and surgery and the surgical procedure itself is challenging requiring thoracotomy, aortic cross clamping, blood transfusion as well as prolonged hospital stay in some cases. Operative mortality is especially high in patients with critical mesenteric or renal ischaemia. The past decade has experienced the emergence of a number of interventional radiological or minimally invasive techniques which have significantly improved the management of patients with aortic dissection. These include stent grafting for entry site closure to prevent aneurysmatic widening of the false lumen as well as percutaneous techniques such as balloon fenestration of the intimal flap and aortic true lumen stenting to alleviate branch vessel ischaemia. False lumen thrombosis following entry closure with stent grafts has been observed in 86-100% of patients, whereas percutaneous interventions are able to effectively relieve organ ischaemia in approximately 90% of the cases. In the years to come, it is to be expected that these endoluminal techniques will become the method of choice for treating most type-B dissections and will assist in significantly reducing the number of open surgical procedures required for type-A dissections. The intention of this article is to provide an overview of the current status of these endoluminal techniques based on our own experience as well as on a review of the relevant literature. (orig.)

  18. Risk Stratification of Patients with Peripheral Arterial Disease and Abdominal Aortic Aneurysm Using Aortic Augmentation Index.

    Science.gov (United States)

    Beckmann, Marianne; Jacomella, Vincenzo; Kohler, Malcom; Lachat, Mario; Salem, Amr; Amann-Vesti, Beatrice; Husmann, Marc

    2015-01-01

    Central augmentation index (cAIx) is an indicator for vascular stiffness. Obstructive and aneurysmatic vascular disease can affect pulse wave propagation and reflection, causing changes in central aortic pressures. To assess and compare cAIx in patients with peripheral arterial disease (PAD) and / or abdominal aortic aneurysm (AAA). cAIx was assessed by radial applanation tonometry (Sphygmocor) in a total of 184 patients at a tertiary referral centre. Patients were grouped as having PAD only, AAA only, or both AAA and PAD. Differences in cAIx measurements between the three patient groups were tested by non-parametric tests and stepwise multivariate linear regression analysis to investigate associations with obstructive or aneurysmatic patterns of vascular disease. In the study sample of 184 patients, 130 had PAD only, 20 had AAA only, and 34 patients had both AAA and PAD. Mean cAIx (%) was 30.5 ± 8.2 across all patients. It was significantly higher in females (35.2 ± 6.1, n = 55) than males (28.4 ± 8.2, n = 129), and significantly higher in patients over 80 years of age (34.4 ± 6.9, n = 22) than in those under 80 years (30.0 ± 8.2, n = 162). Intergroup comparison revealed a significant difference in cAIx between the three patient groups (AAA: 27.3 ± 9.5; PAD: 31.4 ± 7.8; AAA & PAD: 28.8 ± 8.5). cAIx was significantly lower in patients with AAA, higher in patients with both AAA and PAD, and highest in patients with PAD only (beta = 0.21, p = 0.006). Non-invasive assessment of arterial stiffness in high-risk patients indicates that cAIx differs according to the pattern of vascular disease. Measurements revealed significantly higher cAIx values for patients with obstructive peripheral arterial disease than for patients with aneurysmatic disease.

  19. Risk Stratification of Patients with Peripheral Arterial Disease and Abdominal Aortic Aneurysm Using Aortic Augmentation Index.

    Directory of Open Access Journals (Sweden)

    Marianne Beckmann

    Full Text Available Central augmentation index (cAIx is an indicator for vascular stiffness. Obstructive and aneurysmatic vascular disease can affect pulse wave propagation and reflection, causing changes in central aortic pressures.To assess and compare cAIx in patients with peripheral arterial disease (PAD and / or abdominal aortic aneurysm (AAA.cAIx was assessed by radial applanation tonometry (Sphygmocor in a total of 184 patients at a tertiary referral centre. Patients were grouped as having PAD only, AAA only, or both AAA and PAD. Differences in cAIx measurements between the three patient groups were tested by non-parametric tests and stepwise multivariate linear regression analysis to investigate associations with obstructive or aneurysmatic patterns of vascular disease.In the study sample of 184 patients, 130 had PAD only, 20 had AAA only, and 34 patients had both AAA and PAD. Mean cAIx (% was 30.5 ± 8.2 across all patients. It was significantly higher in females (35.2 ± 6.1, n = 55 than males (28.4 ± 8.2, n = 129, and significantly higher in patients over 80 years of age (34.4 ± 6.9, n = 22 than in those under 80 years (30.0 ± 8.2, n = 162. Intergroup comparison revealed a significant difference in cAIx between the three patient groups (AAA: 27.3 ± 9.5; PAD: 31.4 ± 7.8; AAA & PAD: 28.8 ± 8.5. cAIx was significantly lower in patients with AAA, higher in patients with both AAA and PAD, and highest in patients with PAD only (beta = 0.21, p = 0.006.Non-invasive assessment of arterial stiffness in high-risk patients indicates that cAIx differs according to the pattern of vascular disease. Measurements revealed significantly higher cAIx values for patients with obstructive peripheral arterial disease than for patients with aneurysmatic disease.

  20. Traumatic aortic transection with intraluminal aortic fat: transesophageal echocardiographic characteristics and implications.

    Science.gov (United States)

    Sumner, Andrew D; Bobin, John J; Mehta, Sanjay; Stephenson, Edward R

    2003-11-01

    Aortic transection can be a catastrophic complication of blunt chest trauma. Transesophageal echocardiography is a useful tool for assessing aortic pathology. Presented is a case of traumatic aortic transection in which periaortic fat was found within the aortic lumen. Transesophageal echocardiographic characteristics are reviewed and clinical implications discussed.

  1. Acute Right Coronary Ostial Stenosis during Aortic Valve Replacement

    Directory of Open Access Journals (Sweden)

    Sarwar Umran

    2012-01-01

    Full Text Available We report a rare case of acute right coronary artery stenosis developing in a patient undergoing aortic valve replacement. We present a case report with a brief overview of the literature relating to coronary artery occlusion associated with cardiac valve surgery - the theories and treatments are discussed. A 85 year-old female was admitted under the care of the cardiothoracic team with signs and symptoms of heart failure. Investigations, including cardiac echocardiography and coronary angiography, indicated a critical aortic valve stenosis. Intraoperative right ventricular failure ensued post aortic valve replacement. Subsequent investigations revealed an acute occlusion of the proximal right coronary artery with resultant absence of distal flow supplying the right ventricle. An immediate right coronary artery bypass procedure was performed with resolution of the right ventricular failure. Subsequent weaning off cardiopulmonary bypass was uneventful and the patient continued to make excellent recovery in the postoperative phase. To our knowledge this is one of the few documented cases of intraoperative acute coronary artery occlusion developing during valve surgery. However, surgeons should be aware of the potential for acute occlusion so that early recognition and rapid intervention can be instituted.

  2. Aortic aneurysm and diverticulum of Kommerell: a dreadful concomitance

    Directory of Open Access Journals (Sweden)

    Fernando Peixoto Ferraz de Campos

    2012-12-01

    Full Text Available First described in 1936, the diverticulum of Kommerell (DOK is a dilatation of the proximal segment of an aberrant subclavian artery. Appearing more frequently in the left-sided aortic arch, the aberrant right subclavian artery passes behind the esophagus toward the right arm, causing symptoms in the minority of cases. Diagnosis is generally incidental with this pattern. When symptomatic, dysphagia, respiratory symptoms, hoarseness, chest pain, and upper limb ischemia are the most common complaints. Although debatable, the origin of DOK is accepted as being degenerative or congenital. The degenerative condition is normally associated with atherosclerosis and occurs more frequently after the age of 50 years with no gender predominance. Complications may be life threatening and are more commonly related to the diverticulum aneurysm or when associated with aortic diseases such as aneurysms or dissection. The authors present a case of a 67-year-old male with a history of acute chest pain, neurological disturbances, and hypertensive crisis. The diagnostic workup revealed an aortic arch aneurysm with intramural hematoma and a diverticulum aneurysm of Kommerell. Treatment was conservative at first. The patient presented a satisfactory outcome and was referred to an outpatient clinic for follow up and further therapeutic consolidation.

  3. A new murine model of endovascular aortic aneurysm repair.

    Science.gov (United States)

    Rouer, Martin; Meilhac, Olivier; Delbosc, Sandrine; Louedec, Liliane; Pavon-Djavid, Graciela; Cross, Jane; Legagneux, Josette; Bouilliant-Linet, Maxime; Michel, Jean-Baptiste; Alsac, Jean-Marc

    2013-07-07

    Endovascular aneurysm exclusion is a validated technique to prevent aneurysm rupture. Long-term results highlight technique limitations and new aspects of Abdominal aortic aneurysm (AAA) pathophysiology. There is no abdominal aortic aneurysm endograft exclusion model cheap and reproducible, which would allow deep investigations of AAA before and after treatment. We hereby describe how to induce, and then to exclude with a covered coronary stentgraft an abdominal aortic aneurysm in a rat. The well known elastase induced AAA model was first reported in 1990(1) in a rat, then described in mice(2). Elastin degradation leads to dilation of the aorta with inflammatory infiltration of the abdominal wall and intra luminal thrombus, matching with human AAA. Endovascular exclusion with small covered stentgraft is then performed, excluding any interactions between circulating blood and the aneurysm thrombus. Appropriate exclusion and stentgraft patency is confirmed before euthanasia by an angiography thought the left carotid artery. Partial control of elastase diffusion makes aneurysm shape different for each animal. It is difficult to create an aneurysm, which will allow an appropriate length of aorta below the aneurysm for an easy stentgraft introduction, and with adequate proximal and distal neck to prevent endoleaks. Lots of failure can result to stentgraft introduction which sometimes lead to aorta tear with pain and troubles to stitch it, and endothelial damage with post op aorta thrombosis. Giving aspirin to rats before stentgraft implantation decreases failure rate without major hemorrhage. Clamping time activates neutrophils, endothelium and platelets, and may interfere with biological analysis.

  4. Validity and reliability of three methods of stiffness assessment

    National Research Council Canada - National Science Library

    Elizabeth C.Pruyn Mark L.Watsford Aron J.Murphy

    2016-01-01

    ... and reliability of 3 in vivo methods of stiffness assessment using 1 cohort of participants.Methods:To determine inter-day reliability,15 female netballers were assessed for stiffness twice within 1 week using unilateral hopping(vertical stiffness...

  5. Synchronous Carotid Bifurcation Endarterectomy and Retrograde Kissing Stenting of the Innominate and Left Common Carotid Artery in a Patient with a Bovine Aortic Arch

    OpenAIRE

    Alessandro Robaldo; Guido Carignano; Alberto Balderi; Claudio Novali

    2017-01-01

    Management of the symptomatic multiple stenosis of supra-aortic vessels (MSSVs) in a “bovine” aortic arch (BAA) configuration is infrequently reported. The optimal treatment choice remains debatable. A successful hybrid treatment for a proximal critical stenosis of the innominate and left common carotid artery was performed in a high-risk patient with a tandem symptomatic lesion in the right carotid bifurcation and a concentric vulnerable plaque in the bovine trunk. This case supports the fea...

  6. Abdominal aortic feminism.

    Science.gov (United States)

    Mortimer, Alice Emily

    2014-11-14

    A 79-year-old woman presented to a private medical practice 2 years previously for an elective ultrasound screening scan. This imaging provided the evidence for a diagnosis of an abdominal aortic aneurysm (AAA) to be made. Despite having a number of recognised risk factors for an AAA, her general practitioner at the time did not follow the guidance set out by the private medical professional, that is, to refer the patient to a vascular specialist to be entered into a surveillance programme and surgically evaluated. The patient became symptomatic with her AAA, was admitted to hospital and found to have a tender, symptomatic, 6 cm leaking AAA. She consented for an emergency open AAA repair within a few hours of being admitted to hospital, despite the 50% perioperative mortality risk. The patient spent 4 days in intensive care where she recovered well. She was discharged after a 12 day hospital stay but unfortunately passed away shortly after her discharge from a previously undiagnosed gastric cancer. 2014 BMJ Publishing Group Ltd.

  7. Dynamic stiffness of suction caissons - vertical vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Ibsen, Lars Bo; Liingaard, M.; Andersen, Lars

    2006-12-15

    The dynamic response of offshore wind turbines are affected by the properties of the foundation and the subsoil. The purpose of this report is to evaluate the dynamic soil-structure interaction of suction caissons for offshore wind turbines. The investigation is limited to a determination of the vertical dynamic stiffness of suction caissons. The soil surrounding the foundation is homogenous with linear viscoelastic properties. The dynamic stiffness of the suction caisson is expressed by dimensionless frequency-dependent dynamic stiffness coefficients corresponding to the vertical degree of freedom. The dynamic stiffness coefficients for the foundations are evaluated by means of a dynamic three-dimensional coupled Boundary Element/Finite Element model. Comparisons are made with known analytical and numerical solutions in order to evaluate the static and dynamic behaviour of the Boundary Element/Finite Element model. The vertical frequency dependent stiffness has been determined for different combinations of the skirt length, Poisson's ratio and the ratio between soil stiffness and skirt stiffness. Finally the dynamic behaviour at high frequencies is investigated. (au)

  8. Observer-Based Human Knee Stiffness Estimation.

    Science.gov (United States)

    Misgeld, Berno J E; Luken, Markus; Riener, Robert; Leonhardt, Steffen

    2017-05-01

    We consider the problem of stiffness estimation for the human knee joint during motion in the sagittal plane. The new stiffness estimator uses a nonlinear reduced-order biomechanical model and a body sensor network (BSN). The developed model is based on a two-dimensional knee kinematics approach to calculate the angle-dependent lever arms and the torques of the muscle-tendon-complex. To minimize errors in the knee stiffness estimation procedure that result from model uncertainties, a nonlinear observer is developed. The observer uses the electromyogram (EMG) of involved muscles as input signals and the segmental orientation as the output signal to correct the observer-internal states. Because of dominating model nonlinearities and nonsmoothness of the corresponding nonlinear functions, an unscented Kalman filter is designed to compute and update the observer feedback (Kalman) gain matrix. The observer-based stiffness estimation algorithm is subsequently evaluated in simulations and in a test bench, specifically designed to provide robotic movement support for the human knee joint. In silico and experimental validation underline the good performance of the knee stiffness estimation even in the cases of a knee stiffening due to antagonistic coactivation. We have shown the principle function of an observer-based approach to knee stiffness estimation that employs EMG signals and segmental orientation provided by our own IPANEMA BSN. The presented approach makes realtime, model-based estimation of knee stiffness with minimal instrumentation possible.

  9. Novel SMAD3 Mutation in a Patient with Hypoplastic Left Heart Syndrome with Significant Aortic Aneurysm

    Directory of Open Access Journals (Sweden)

    Kristi K. Fitzgerald

    2014-01-01

    Full Text Available Aneurysms-osteoarthritis syndrome (AOS caused by haploinsufficiency of SMAD3 is a recently described cause of syndromic familial thoracic aortic aneurysm and dissection (TAAD. We identified a novel SMAD3 mutation in a patient with hypoplastic left heart syndrome (HLHS who developed progressive aortic aneurysm requiring surgical replacement of the neoaortic root, ascending aorta, and proximal aortic arch. Family screening for the mutation revealed that his father, who has vascular and skeletal features of AOS, and his brother, who is asymptomatic, also have the pathogenic mutation. This is the first case report of a SMAD3 mutation in a patient with hypoplastic left heart syndrome. This case highlights the importance of genetic testing for known causes of aneurysm in patients with congenital heart disease who develop aneurysmal disease as it may significantly impact the management of those patients and their family members.

  10. Can aortic elastic parameters be used for the diagnosis of volume overload in patients with end stage renal disease.

    Science.gov (United States)

    Sayin, Muhammet R; Akpinar, Ibrahim; Cetiner, Mehmet A; Karabag, Turgut; Aydin, Mustafa; Hur, Ender; Dogan, Sait M

    2012-01-01

    We aimed here to investigate hydration status by echocardiography in end stage renal disease (ESRD) patients. 25 ESRD patients [15 males; mean age: 54.0±16.6 years; 13 hemodialysis; 12 peritoneal dialysis] were considered eligible for this study. We also examined 29 healthy volunteers as a control group (17 males; mean age: 46.5±12.8 years). Body composition analysis using the bioimpedance spectroscopy technique was performed for volume overload diagnosis. The ratio of extracellular water (ECW) to height was used as volume indices. The aortic elastic parameters were calculated by echocardiography. A correlation analyses was performed between the ratio of ECW to height indicating the volume overload and the aortic elastic parameters e.g. Aortic strain (AS), Aortic distensibility (AD) and Aortic stiffness index (ASI). The ratio of ECW to height that indicates volume overload in ESRD patients was considerably higher than that in the control group (10.25±1.98 L/m vs. 8.66±1.22 L/m, p=0.001). There was a negative correlation between the ratio of ECW to height and AS and AD and a positive correlation between the ratio of ECW to height and ASI. Given the importance of the diagnosis and follow up of volume overload, the results show that aortic elasticity measurements, being easy to perform and replicate, can be used for this purpose. Copyright © 2012 S. Karger AG, Basel.

  11. Hybrid Palliation for Interrupted Aortic Arch With Small Aortic Valve.

    Science.gov (United States)

    Uno, Yoshimasa; Masuoka, Ayumu; Hotoda, Kentarou; Katogi, Toshiyuki; Suzuki, Takaaki

    2017-05-01

    Open heart surgery for interrupted aortic arch in the neonatal period is still a high-risk procedure related in part to patient factors such as low birth weight, other morphologic anomalies, and, especially, small aortic valve size. Recently, we performed hybrid palliation with bilateral pulmonary artery banding and ductal stenting as the first-stage palliation for such cases. In this study, the outcomes of this procedure were examined. Six cases of interrupted aortic arch with a small aortic valve underwent the hybrid procedure in the neonatal period in our institute from 2010 to 2015 (mean age: 6.8 days, mean body weight: 3.2 kg, mean z score of the aortic valve annulus: -8.3). Their postoperative clinical courses and results of the second-stage surgery were evaluated. No mortality or severe morbidity was seen in association with initial hybrid palliation. Five of six patients were discharged from the hospital; the one exception had a significant urinary tract anomaly. None needed an additional catheter intervention or surgical procedure postoperatively. All surviving patients underwent second-stage surgery; three had biventricular repair by the conventional method or Damus-Kaye-Stansel anastomosis with the Rastelli procedure and the other three proceeded toward staged Fontan reconstruction. Growth of the aortic valve was seen in four patients, and increased indexed left ventricle volume was recognized in one after the palliation. Hybrid palliation could be useful not only to avoid high-risk neonatal surgery but also to allow for eventual selection of the second-stage surgery based on the observations of potential interval development of left ventricular structures.

  12. A History of Thoracic Aortic Surgery.

    Science.gov (United States)

    McFadden, Paul Michael; Wiggins, Luke M; Boys, Joshua A

    2017-08-01

    Ancient historical texts describe the presence of aortic pathology conditions, although the surgical treatment of thoracic aortic disease remained insurmountable until the 19th century. Surgical treatment of thoracic aortic disease then progressed along with advances in surgical technique, conduit production, cardiopulmonary bypass, and endovascular technology. Despite radical advances in aortic surgery, principles established by surgical pioneers of the 19th century hold firm to this day. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. The use of a new hybrid stentgraft for the repair of extensive thoracic aortic aneurysms with the frozen elephant trunk method - first Polish experiences.

    Science.gov (United States)

    Zembala, Michał; Krasoń, Marcin; Hrapkowicz, Tomasz; Przybylski, Roman; Filipiak, Krzysztof; Borowicz, Marcin; Niklewski, Tomasz; Głowacki, Jan; Wolny, Tomasz; Nadziakiewicz, Paweł; Walas, Ryszard; Zembala, Marian

    2014-09-01

    The frozen elephant trunk (FET) technique is a modification of the traditional elephant trunk method, which was introduced by Borst in 1983 in order to treat extensive thoracic aortic aneurysms. The crux of the new method is the different type of aortic prosthesis, consisting of a Dacron part (with or without branches leading to the arterial vessels which exit the aortic arch) and a port for extracorporeal circulation with a self-expanding nitinol stentgraft. This combination enables a complete one-stage treatment of the pathologies within the arch and the proximal segment of the descending aorta; moreover, it facilitates the performance of a two-stage hybrid treatment of extensive thoracic aortic aneurysms involving a significant part of the descending aorta. This article presents the cases of four patients with extensive aortic disease, who were implanted with Thoraflex prostheses (Vascutek, Scotland).

  14. The use of a new hybrid stentgraft for the repair of extensive thoracic aortic aneurysms with the frozen elephant trunk method – first Polish experiences

    Science.gov (United States)

    Krasoń, Marcin; Hrapkowicz, Tomasz; Przybylski, Roman; Filipiak, Krzysztof; Borowicz, Marcin; Niklewski, Tomasz; Głowacki, Jan; Wolny, Tomasz; Nadziakiewicz, Paweł; Walas, Ryszard; Zembala, Marian

    2014-01-01

    The frozen elephant trunk (FET) technique is a modification of the traditional elephant trunk method, which was introduced by Borst in 1983 in order to treat extensive thoracic aortic aneurysms. The crux of the new method is the different type of aortic prosthesis, consisting of a Dacron part (with or without branches leading to the arterial vessels which exit the aortic arch) and a port for extracorporeal circulation with a self-expanding nitinol stentgraft. This combination enables a complete one-stage treatment of the pathologies within the arch and the proximal segment of the descending aorta; moreover, it facilitates the performance of a two-stage hybrid treatment of extensive thoracic aortic aneurysms involving a significant part of the descending aorta. This article presents the cases of four patients with extensive aortic disease, who were implanted with Thoraflex prostheses (Vascutek, Scotland). PMID:26335241

  15. The effect of physical exercise on arterial stiffness parameters in young sportsmen.

    Science.gov (United States)

    Rátgéber, László; Lenkey, Zsófia; Németh, Ádám; Hidvégi, Erzsébet; Husznai, Róbert; Verzár, Zsófia; Miklós, Illyés; Bódis, József; Cziráki, Attila

    2015-02-01

    This study aimed to determine the effect of single-bout exercise on aortic stiffness parameters in young basketball players. A total of 108 young male subjects (mean age 14.2 ± 3.4 years) were enrolled into the study. Simultaneous measure- ment of aortic pulse wave velocity (PWVao) and augmentation index (Alxao) were performed with the oscillometric, occlusive device. Echocardiographic parameters of left ventricular systolic and diastolic function at rest were also measured in sportsmen. We did not find significant differences of resting PWVao in comparison with young sportsmen (S) and age-matched healthy volunteers (V): 5.82 ± 0.14 m/s vs 5.83 ± 0.12 m/s for S and V groups, respectively. The values of PWVao measured after dynamic exercise, isometric exercise, and rest were 8.0 ± 0.5 m/s, 5.86 ± 0.1 m/s and 5.82 ± 0.1 m/s, respectively. We confirmed that values after dynamic exercise are significantly different from those after isometric exercise (P exercise in the three groups (11.7 ± 7% vs 3.8 ± 3% vs- 0.9 ± 0.9% for groups 1, 2, and 3, respectively). We applied a feasible, clinically useful method which allowed us to measure changes in aortic PWV and Alx during acute, single-bout exercise on the basketball court in young sportsmen.

  16. Research on Detection of Machine Stiffness

    Directory of Open Access Journals (Sweden)

    Wang Li-Jie

    2015-01-01

    Full Text Available Machine tool stiffness is a principal factor affecting machine tool precision, traditional methods can only be used to detect limited categories of machine tools. The paper introduces a new scheme to detect machine tool stiffness on the basis of dynamic detection of machine tool stiffness considering its characteristics and stress state during processing. An experiment conducted in turn-milling machining center CH7516GS indicated by comparison that statics analysis of finite elements matched the experimental result well, which provided precise original data for design of improved machine tool precision and access to design of precision detection equipment for other types of machine tools.

  17. α-B Crystallin Reverses High Diastolic Stiffness of Failing Human Cardiomyocytes.

    Science.gov (United States)

    Franssen, Constantijn; Kole, Jeroen; Musters, René; Hamdani, Nazha; Paulus, Walter J

    2017-03-01

    Cardiomyocytes with a less distensible titin and interstitial collagen contribute to the high diastolic stiffness of failing myocardium. Their relative contributions and mechanisms underlying loss of titin distensibility were assessed in failing human hearts. Left ventricular tissue was procured in patients with aortic stenosis (AS, n=9) and dilated cardiomyopathy (DCM, n=6). Explanted donor hearts (n=8) served as controls. Stretches were performed in myocardial strips, and an extraction protocol differentiated between passive tension (Fpassive) attributable to cardiomyocytes or to collagen. Fpassive-cardiomyocytes was higher in AS and DCM at shorter muscle lengths, whereas Fpassive-collagen was higher in AS at longer muscle lengths and in DCM at shorter and longer muscle lengths. Cardiomyocytes were stretched to investigate titin distensibility. Cardiomyocytes were incubated with alkaline phosphatase, subsequently reassessed after a period of prestretch and finally treated with the heat shock protein α-B crystallin. Alkaline phosphatase shifted the Fpassive-sarcomere length relation upward only in donor. Prestretch shifted the Fpassive-sarcomere length relation further upward in donor and upward in AS and DCM. α-B crystallin shifted the Fpassive-sarcomere length relation downward to baseline in donor and to lower than baseline in AS and DCM. In failing myocardium, confocal laser microscopy revealed α-B crystallin in subsarcolemmal aggresomes. High cardiomyocyte stiffness contributed to stiffness of failing human myocardium because of reduced titin distensibility. The latter resulted from an absent stiffness-lowering effect of baseline phosphorylation and from titin aggregation. High cardiomyocyte stiffness was corrected by α-B crystallin probably through relief of titin aggregation. © 2017 American Heart Association, Inc.

  18. Effect of lysyl oxidase inhibition on angiotensin II-induced arterial hypertension, remodeling, and stiffness.

    Directory of Open Access Journals (Sweden)

    Lance S Eberson

    Full Text Available It is well accepted that angiotensin II (Ang II induces altered vascular stiffness through responses including both structural and material remodeling. Concurrent with remodeling is the induction of the enzyme lysyl oxidase (LOX through which ECM proteins are cross-linked. The study objective was to determine the effect of LOX mediated cross-linking on vascular mechanical properties. Three-month old mice were chronically treated with Ang II with or without the LOX blocker, β -aminopropionitrile (BAPN, for 14 days. Pulse wave velocity (PWV from Doppler measurements of the aortic flow wave was used to quantify in vivo vascular stiffness in terms of an effective Young's modulus. The increase in effective Young's modulus with Ang II administration was abolished with the addition of BAPN, suggesting that the material properties are a major controlling element in vascular stiffness. BAPN inhibited the Ang II induced collagen cross-link formation by 2-fold and PWV by 44% (P<0.05. Consistent with this observation, morphometric analysis showed that BAPN did not affect the Ang II mediated increase in medial thickness but significantly reduced the adventitial thickness. Since the hypertensive state contributes to the measured in vivo PWV stiffness, we removed the Ang II infusion pumps on Day 14 and achieved normal arterial blood pressures. With pump removal we observed a decrease of the PWV in the Ang II group to 25% above that of the control values (P=0.002, with a complete return to control values in the Ang II plus BAPN group. In conclusion, we have shown that the increase in vascular stiffness with 14 day Ang II administration results from a combination of hypertension-induced wall strain, adventitial wall thickening and Ang II mediated LOX ECM cross-linking, which is a major material source of vascular stiffening, and that the increased PWV was significantly inhibited with co-administration of BAPN.

  19. Aortic root replacement with a pulmonary autograft

    NARCIS (Netherlands)

    R.B. Hokken (Raymond)

    1997-01-01

    textabstractAortic valve disease in the pediatric age group is usually a consequence of congenital aortic stenosis, which may be isolated or may be a part of an anomaly of the left ventricular outflow tract or the aortic root. Management of these patients is difficult. Neonates and infants

  20. Some Properties of Fuzzy Soft Proximity Spaces

    Science.gov (United States)

    Demir, İzzettin; Özbakır, Oya Bedre

    2015-01-01

    We study the fuzzy soft proximity spaces in Katsaras's sense. First, we show how a fuzzy soft topology is derived from a fuzzy soft proximity. Also, we define the notion of fuzzy soft δ-neighborhood in the fuzzy soft proximity space which offers an alternative approach to the study of fuzzy soft proximity spaces. Later, we obtain the initial fuzzy soft proximity determined by a family of fuzzy soft proximities. Finally, we investigate relationship between fuzzy soft proximities and proximities. PMID:25793224

  1. [MINIMALLY INVASIVE AORTIC VALVE REPLACEMENT].

    Science.gov (United States)

    Tabata, Minoru

    2016-03-01

    Minimally invasive aortic valve replacement (MIAVR) is defined as aortic valve replacement avoiding full sternotomy. Common approaches include a partial sternotomy right thoracotomy, and a parasternal approach. MIAVR has been shown to have advantages over conventional AVR such as shorter length of stay and smaller amount of blood transfusion and better cosmesis. However, it is also known to have disadvantages such as longer cardiopulmonary bypass and aortic cross-clamp times and potential complications related to peripheral cannulation. Appropriate patient selection is very important. Since the procedure is more complex than conventional AVR, more intensive teamwork in the operating room is essential. Additionally, a team approach during postoperative management is critical to maximize the benefits of MIAVR.

  2. Aortic Function's Adaptation in Response to Exercise-Induced Stress Assessing by 1.5T MRI: A Pilot Study in Healthy Volunteers.

    Directory of Open Access Journals (Sweden)

    Laurence Bal-Theoleyre

    Full Text Available Evaluation of the aortic "elastic reserve" might be a relevant marker to assess the risk of aortic event. Our aim was to compare regional aortic elasticity at rest and during supine bicycle exercise at 1.5 T MRI in healthy individuals.Fifteen volunteers (8 men, with a mean age of 29 (23-41 years, completed the entire protocol. Images were acquired immediately following maximal exercise. Retrospective cine sequences were acquired to assess compliance, distensibility, maximum rates of systolic distension and diastolic recoil at four different locations: ascending aorta, proximal descending aorta, distal descending aorta and aorta above the coeliac trunk level. Segmental aortic pulse wave velocity (PWV was assessed by through plane velocity-encoded MRI.Exercise induced a significant decrease of aortic compliance and distensibility, and a significant increase of the absolute values of maximum rates of systolic distension and diastolic recoil at all sites (p<10-3. At rest and during stress, ascending aortic compliance was statistically higher compared to the whole descending aorta (p≤0.0007. We found a strong correlation between the rate pressure product and aortic distensibility at all sites (r = - 0.6 to -0.75 according to the site, p<10-4. PWV measured at the proximal and distal descending aorta increased significantly during stress (p = 0.02 and p = 0.008, respectively.Assessment of regional aortic function during exercise is feasible using MRI. During stress, aortic elasticity decreases significantly in correlation with an increase of the PWV. Further studies are required to create thresholds for ascending aorta dysfunction among patients with aneurysms, and to monitor the impact of medication on aortic remodeling.

  3. PROXIMITY MANAGEMENT IN CRISIS CONDITIONS

    Directory of Open Access Journals (Sweden)

    Ion Dorin BUMBENECI

    2010-01-01

    Full Text Available The purpose of this study is to evaluate the level of assimilation for the terms "Proximity Management" and "Proximity Manager", both in the specialized literature and in practice. The study has two parts: the theoretical research of the two terms, and an evaluation of the use of Proximity management in 32 companies in Gorj, Romania. The object of the evaluation resides in 27 companies with less than 50 employees and 5 companies with more than 50 employees.

  4. Programmable variable stiffness 2D surface design

    Science.gov (United States)

    Trabia, Sarah; Hwang, Taeseon; Yim, Woosoon

    2014-03-01

    Variable stiffness features can contribute to many engineering applications ranging from robotic joints to shock and vibration mitigation. In addition, variable stiffness can be used in the tactile feedback to provide the sense of touch to the user. A key component in the proposed device is the Biased Magnetorheological Elastomer (B-MRE) where iron particles within the elastomer compound develop a dipole interaction energy. A novel feature of this device is to introduce a field induced shear modulus bias via a permanent magnet which provides an offset with a current input to the electromagnetic control coil to change the compliance or modulus of a base elastomer in both directions (softer or harder). The B-MRE units can lead to the design of a variable stiffness surface. In this preliminary work, both computational and experimental results of the B-MRE are presented along with a preliminary design of the programmable variable stiffness surface design.

  5. Stiff Neck, Torticollis, and Pseudotumor Cerebri

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2002-05-01

    Full Text Available Three prepubertal children diagnosed with pseudotumor cerebri and presenting with stiff neck and torticollis are reported from Schneider Children’s Medical Center, Sackler School of Medicine, Tel Aviv, Israel.

  6. Strength and stiffness of engineering systems

    CERN Document Server

    Leckie, Frederick A

    2009-01-01

    This book on the stiffness and strength of engineering systems integrates a wide array of topics into a unified text, including plasticity, fracture, composite materials, energy approaches, and mechanics of microdevices (MEMs)..

  7. Macroscopic stiffness of breast tumors predicts metastasis.

    Science.gov (United States)

    Fenner, Joseph; Stacer, Amanda C; Winterroth, Frank; Johnson, Timothy D; Luker, Kathryn E; Luker, Gary D

    2014-07-01

    Mechanical properties of tumors differ substantially from normal cells and tissues. Changes in stiffness or elasticity regulate pro-metastatic behaviors of cancer cells, but effects have been documented predominantly in isolated cells or in vitro cell culture systems. To directly link relative stiffness of tumors to cancer progression, we combined a mouse model of metastatic breast cancer with ex vivo measurements of bulk moduli of freshly excised, intact tumors. We found a high, inverse correlation between bulk modulus of resected tumors and subsequent local recurrence and metastasis. More compliant tumors were associated with more frequent, larger local recurrences and more extensive metastases than mice with relatively stiff tumors. We found that collagen content of resected tumors correlated with bulk modulus values. These data establish that relative differences in tumor stiffness correspond with tumor progression and metastasis, supporting further testing and development of tumor compliance as a prognostic biomarker in breast cancer.

  8. Aortic valve dysfunction and aortic dilation in adults with coarctation of the aorta.

    Science.gov (United States)

    Clair, Mathieu; Fernandes, Susan M; Khairy, Paul; Graham, Dionne A; Krieger, Eric V; Opotowsky, Alexander R; Singh, Michael N; Colan, Steven D; Meijboom, Erik J; Landzberg, Michael J

    2014-01-01

    To determine the prevalence of aortic valve dysfunction, aortic dilation, and aortic valve and ascending aortic intervention in adults with coarctation of the aorta (CoA). Aortic valve dysfunction and aortic dilation are rare among children and adolescents with CoA. With longer follow-up, adults may be more likely to have progressive disease. We retrospectively reviewed all adults with CoA, repaired or unrepaired, seen at our center between 2004 and 2010. Two hundred sixteen adults (56.0% male) with CoA were identified. Median age at last evaluation was 28.3 (range 18.0 to 75.3) years. Bicuspid aortic valve (BAV) was present in 65.7%. At last follow-up, 3.2% had moderate or severe aortic stenosis, and 3.7% had moderate or severe aortic regurgitation. Dilation of the aortic root or ascending aorta was present in 28.0% and 41.6% of patients, respectively. Moderate or severe aortic root or ascending aortic dilation (z-score > 4) was present in 8.2% and 13.7%, respectively. Patients with BAV were more likely to have moderate or severe ascending aortic dilation compared with those without BAV (19.5% vs. 0%; P aortic dilation (P = 0.04). At most recent follow-up, 5.6% had undergone aortic valve intervention, and 3.2% had aortic root or ascending aortic replacement. In adults with CoA, significant aortic valve dysfunction and interventions during early adulthood were uncommon. However, aortic dilation was prevalent, especially of the ascending aorta, in patients with BAV. © 2013 Wiley Periodicals, Inc.

  9. The association of muscle and tendon elasticity with passive joint stiffness: In vivo measurements using ultrasound shear wave elastography.

    Science.gov (United States)

    Chino, Kentaro; Takahashi, Hideyuki

    2015-12-01

    Passive joint stiffness is associated with various tissues, including muscles, tendons, ligaments, and joint capsules. The specific elasticity of muscles or tendons can be measured using ultrasound shear wave elastography. To examine the association of muscle and tendon elasticity with passive joint stiffness, in vivo measurements of muscle and tendon elasticity were performed using ultrasound shear wave elastography. In 25 subjects, passive ankle joint stiffness was determined using the joint angle-passive torque relationship. The stiffness index of the muscle belly of the medial gastrocnemius (MG)--influenced by the muscle fascicles, its aponeuroses, and the proximal tendon--was quantified by the displacement of the muscle-tendon junction, which was visualized using B-mode ultrasonography during passive dorsiflexion. The stiffness index of the Achilles tendon--influenced by the tendon and the ligaments and joint capsule of the ankle--was similarly determined. The MG and Achilles tendon elasticity was measured using ultrasound shear wave elastography. Simple regression indicated a significant correlation between passive joint stiffness and stiffness index of the MG muscle belly (r=0.80) and Achilles tendon (r=0.60), but no correlation with elasticity of the MG (r=-0.37) or Achilles tendon (r=-0.39). Individual variations in the elasticity of either the MG or Achilles tendon are not associated with variations in passive ankle joint stiffness; however, variations in the elasticity of other tissues, including MG aponeuroses or the ligaments and joint capsule of the ankle, would be associated with the variations in joint stiffness. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Transcatheter aortic valve implantation for bicuspid aortic valve stenosis.

    Science.gov (United States)

    Hamdan, Ashraf; Kornowski, Ran

    2015-08-01

    In Preprocedural CT, patients with BAV have larger aortic annulus perimeters, and more calcified valves compared with TAV. In patients with BAV, self-expandable valves were under-expand and balloon-expandable valves have a trend toward increased rates of postimplantation AR grade. Self-expandable valves have higher postprocedural gradient in BAV compared with TAV. © 2015 Wiley Periodicals, Inc.

  11. Stiffness of Railway Soil-Steel Structures

    Directory of Open Access Journals (Sweden)

    Machelski Czesław

    2015-12-01

    Full Text Available The considerable influence of the soil backfill properties and that of the method of compacting it on the stiffness of soil-steel structures is characteristic of the latter. The above factors (exhibiting randomness become apparent in shell deformation measurements conducted during construction and proof test loading. A definition of soil-shell structure stiffness, calculated on the basis of shell deflection under the service load, is proposed in the paper. It is demonstrated that the stiffness is the inverse of the deflection influence function used in structural mechanics. The moving load methodology is shown to be useful for testing, since it makes it possible to map the shell deflection influence line also in the case of group loads (concentrated forces, as in bridges. The analyzed cases show that the shell’s span, geometry (static scheme and the height of earth fill influence the stiffness of the structure. The soil-steel structure’s characteristic parameter in the form of stiffness k is more suitable for assessing the quality of construction works than the proposed in code geometric index ω applied to beam structures. As shown in the given examples, parameter k is more effective than stiffness parameter λ used to estimate the deformation of soil-steel structures under construction. Although the examples concern railway structures, the methodology proposed in the paper is suitable also for road bridges.

  12. Hybrid Repair of Complex Thoracic Aortic Arch Pathology: Long-Term Outcomes of Extra-anatomic Bypass Grafting of the Supra-aortic Trunk

    Energy Technology Data Exchange (ETDEWEB)

    Lotfi, S., E-mail: shamim.lotfi@kcl.ac.uk; Clough, R. E.; Ali, T. [Guy' s and St. Thomas' NHS Trust, Vascular Surgery (United Kingdom); Salter, R. [Guy' s and St. Thomas' NHS Trust, Interventional Radiology (United Kingdom); Young, C. P. [Guy' s and St. Thomas' NHS Trust, Cardiac Surgery (United Kingdom); Bell, R.; Modarai, B.; Taylor, P., E-mail: peter.taylor@gstt.nhs.uk [Guy' s and St. Thomas' NHS Trust, Vascular Surgery (United Kingdom)

    2013-02-15

    Hybrid repair constitutes supra-aortic debranching before thoracic endovascular aortic repair (TEVAR). It offers improved short-term outcome compared with open surgery; however, longer-term studies are required to assess patient outcomes and patency of the extra-anatomic bypass grafts. A prospectively maintained database of 380 elective and urgent patients who had undergone TEVAR (1997-2011) was analyzed retrospectively. Fifty-one patients (34 males; 17 females) underwent hybrid repair. Median age was 71 (range, 18-90) years with mean follow-up of 15 (range, 0-61) months. Perioperative complications included death: 10 % (5/51), stroke: 12 % (6/51), paraplegia: 6 % (3/51), endoleak: 16 % (8/51), rupture: 4 % (2/51), upper-limb ischemia: 2 % (1/51), bypass graft occlusion: 4 % (2/51), and cardiopulmonary complications in 14 % (7/51). Three patients (6 %) required emergency intervention for retrograde dissection: (2 aortic root repairs; 2 innominate stents). Early reintervention was performed for type 1 endoleak in two patients (2 proximal cuff extensions). One patient underwent innominate stenting and revision of their bypass for symptomatic restenosis. At 48 months, survival was 73 %. Endoleak was detected in three (6 %) patients (type 1 = 2; type 2 = 1) requiring debranching with proximal stent graft (n = 2) and proximal extension cuff (n = 1). One patient had a fatal rupture of a mycotic aneurysm and two arch aneurysms expanded. No bypass graft occluded after the perioperative period. Hybrid operations to treat aortic arch disease can be performed with results comparable to open surgery. The longer-term outcomes demonstrate low rates of reintervention and high rates of graft patency.

  13. Associations between glycaemic deterioration and aortic stiffness and central blood pressure

    DEFF Research Database (Denmark)

    Johansen, Nanna B; Rasmussen, Signe S; Wiinberg, Niels

    2017-01-01

    wave velocity (aPWV) and assessment of central blood pressure (BP). We compared differences in central haemodynamics at follow-up between the diabetes risk groups and analysed the impact of HbA1c at screening and HbA1c change on central haemodynamics at follow-up adjusting for relevant confounders....... RESULTS: At screening, median age was 59.0 years, and median HbA1c was 5.7%. At follow-up, median aPWV was 8.0 m/s, and median central SBP was 123.5 mmHg. Among individuals with high DRS, aPWV, central SBP and DBP, and pulse pressure were higher in individuals with impaired glucose tolerance than normal...

  14. Evaluation of aortic stiffness in Gilbert syndrome patients: a protective effect of elevated bilirubin levels.

    Science.gov (United States)

    Yüce, Süleyman; Cüre, Erkan; Çiçek, Yüksel; Cumhur Cüre, Medine; Yılmaz, Arif; Kızılkaya, Bayram

    2015-10-01

    Gilbert's syndrome (GS) is an autosomal recessive disease that is characterized by an increase in indirect bilirubin (IB). The incidence of atherosclerotic heart disease is decreased in GS. This study aimed to investigate the relation between pulse wave velocity (PWV) and the presence of GS. The study included 58 GS patients (32 females, age; 27.12 ± 7.27 years, 26 males, age; 26.63 ± 5.84 years) admitted to the internal medicine clinic of the hospital. The control group included 58 healthy individuals (35 females [27.33 ± 8.06 years old, p=0.716] and 23 males [27.38 ± 6.91 years old, p=0.923]). PWV of both groups was measured from the right carotid and femoral arteries. Mean age of the GS group was 26.03 ± 8.22 years, while that of the healthy group was 26.60 ± 5.84 years. The GS group's diastolic blood pressure and PWV were significantly lower than those of the control group: 67.76 ± 8.59 mmHg vs 71.72 ± 7.28 mmHg; p=0.008, and 5.63 ± 1.12 m/s vs 6.18 ± 1.22 m/s; p=0.014 respectively. The GS group's high density lipoprotein (HDL) level was significantly higher than that of the control group: 1.4 ± 0.3 mmol/L vs 1.2 ± 0.3 mmol/L, p=0.029. This study found PWV among GS patients to be lower than that among non-smoking and aged-matched healthy controls.

  15. Extreme-Dipper Profile, Increased Aortic Stiffness, and Impaired Subendocardial Viability in Hypertension.

    Science.gov (United States)

    Amah, Guy; Ouardani, Rahma; Pasteur-Rousseau, Adrien; Voicu, Sebastian; Safar, Michel E; Kubis, Nathalie; Bonnin, Philippe

    2017-04-01

    In treated hypertensives, extreme-dippers with stable coronary artery disease (CAD) exhibit more severe nighttime cardiac ischemia than dippers. After excluding confounding factors such as diabetes, CAD or chronic kidney disease (CKD), we assessed whether subendocardial viability, determined by the Buckberg index, was more significantly impaired in extreme-dippers than in dippers. Two hundred thirteen consecutive treated hypertensives (156 dippers, 57 extreme-dippers), were included. After 24-hour ambulatory blood pressure (BP) monitoring, patients underwent radial applanation tonometry (with determination of: subendocardial viability ratio [SEVR], central augmentation index [AIx], and pulse pressure amplification [PPamp]), carotid-femoral pulse wave velocity (cfPWV) measurement, and cycle ergometer stress testing. Extreme-dippers showed higher cfPWV (8.99 ± 2.16 vs. 8.29 ± 1.69 m/s, P = 0.014), higher AIx (29.7 ± 9.4 vs. 26.4 ± 10.4%, P = 0.042), lower PPamp (1.22 ± 0.14 vs. 1.30 ± 0.15, P subendocardial viability compared to dippers. Extreme-dipper hypertensive patients, women in particular, may have a significantly higher risk of silent myocardial ischemia, thus justifying systematic screening.

  16. Aortic remodelling in aortic dissection after frozen elephant trunk†.

    Science.gov (United States)

    Dohle, Daniel-Sebastian; Tsagakis, Konstantinos; Janosi, Rolf Alexander; Benedik, Jaroslav; Kühl, Hilmar; Penkova, Liuba; Stebner, Ferdinand; Wendt, Daniel; Jakob, Heinz

    2016-01-01

    Frozen elephant trunk (FET) can be used for continuous downstream aorta treatment in acute aortic dissection (AAD) and chronic aortic dissection (CAD). The study reports the changes in the lumen volumes along the downstream aorta towards remodelling. In 70 patients (22 CAD, 48 AAD), pre-, postoperative and at least the 1-year follow-up aortic imaging was available. Volume changes of aortic lumen (AL) and true lumen (TL) between examinations along the stent graft aortic segment (A), downstream to coeliac trunk (B) and distally to bifurcation (C) were used for quantification. TL increase >10% with stable AL or AL decrease >10% with stable TL were classified as positive, changes within a 10% threshold as stable, and all other changes as negative remodelling. In AAD, positive or stable remodelling occurred in A (90%), B (65%), C (58%) within 1 year, thereafter in 26 patients (follow-up: 47 ± 21 months) in A (92%), B (65%), C (62%). Negative remodelling in ≥2 segments was found in 5/26 (19%) patients. In CAD, positive or stable remodelling occurred in A (100%), B (86%), C (77%) within 1 year, thereafter in 16 patients (follow-up: 46 ± 20 months) in A (75%), B (44%), C (38%). Negative remodelling in ≥2 segments was found in 7/16 (43%) patients, 5 underwent reintervention, and stabilized thereafter. FET facilitates positive remodelling in AAD and CAD down to stent graft level. Distally, 20% AAD and 40% CAD patients remain at risk for secondary reintervention, and can be identified by negative remodelling in ≥2 segments in the follow-up examinations. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  17. Transfemoral transcatheter aortic valve implantation in a patient with a severe aortic stenosis and cardiogenic shock requiring intra-aortic balloon pump support.

    Science.gov (United States)

    Chodór, Piotr; Wilczek, Krzysztof; Przybylski, Roman; Świątkowski, Andrzej; Głowacki, Jan; Kalarus, Zbigniew; Zembala, Marian

    2015-01-01

    The following paper presents a patient with severe aortic stenosis and severely reduced left ventricular ejection fraction with intra-aortic balloon pump counterpulsation support, who underwent transfemoral aortic valve implantation of a CoreValve prosthesis.

  18. Genetic and Epigenetic Regulation of Aortic Aneurysms

    Directory of Open Access Journals (Sweden)

    Ha Won Kim

    2017-01-01

    Full Text Available Aneurysms are characterized by structural deterioration of the vascular wall leading to progressive dilatation and, potentially, rupture of the aorta. While aortic aneurysms often remain clinically silent, the morbidity and mortality associated with aneurysm expansion and rupture are considerable. Over 13,000 deaths annually in the United States are attributable to aortic aneurysm rupture with less than 1 in 3 persons with aortic aneurysm rupture surviving to surgical intervention. Environmental and epidemiologic risk factors including smoking, male gender, hypertension, older age, dyslipidemia, atherosclerosis, and family history are highly associated with abdominal aortic aneurysms, while heritable genetic mutations are commonly associated with aneurysms of the thoracic aorta. Similar to other forms of cardiovascular disease, family history, genetic variation, and heritable mutations modify the risk of aortic aneurysm formation and provide mechanistic insight into the pathogenesis of human aortic aneurysms. This review will examine the relationship between heritable genetic and epigenetic influences on thoracic and abdominal aortic aneurysm formation and rupture.

  19. Genetic and Epigenetic Regulation of Aortic Aneurysms.

    Science.gov (United States)

    Kim, Ha Won; Stansfield, Brian K

    2017-01-01

    Aneurysms are characterized by structural deterioration of the vascular wall leading to progressive dilatation and, potentially, rupture of the aorta. While aortic aneurysms often remain clinically silent, the morbidity and mortality associated with aneurysm expansion and rupture are considerable. Over 13,000 deaths annually in the United States are attributable to aortic aneurysm rupture with less than 1 in 3 persons with aortic aneurysm rupture surviving to surgical intervention. Environmental and epidemiologic risk factors including smoking, male gender, hypertension, older age, dyslipidemia, atherosclerosis, and family history are highly associated with abdominal aortic aneurysms, while heritable genetic mutations are commonly associated with aneurysms of the thoracic aorta. Similar to other forms of cardiovascular disease, family history, genetic variation, and heritable mutations modify the risk of aortic aneurysm formation and provide mechanistic insight into the pathogenesis of human aortic aneurysms. This review will examine the relationship between heritable genetic and epigenetic influences on thoracic and abdominal aortic aneurysm formation and rupture.

  20. Haemolytic anaemia resulting from the surgical repair of acute type A aortic dissection.

    Science.gov (United States)

    Sekine, Yuji; Yamamoto, Shin; Fujikawa, Takuya; Oshima, Susumu; Ono, Makoto; Sasaguri, Shiro

    2014-02-01

    Haemolytic anaemia after acute aortic dissection surgery is extremely rare. We report 4 cases of haemolytic anaemia with different aetiologies. Four patients underwent emergency operation for acute type A aortic dissection and subsequently developed haemolytic anaemia. Case 1: a 41-year old man underwent hemiarch replacement. We performed total arch replacement 3 years postoperatively, which revealed that haemolytic anaemia was induced by proximal anastomotic stenosis caused by inverted internal felt strip. Case 2: a 28-year old man diagnosed with Marfan syndrome underwent total arch replacement. Five months postoperatively, we noted severe stenosis at the previous distal anastomotic site, which caused the haemolytic anaemia, and performed descending thoracic aortic replacement for a residual dissecting aneurysm. Case 3: a 49-year old man underwent hemiarch replacement. Three years postoperatively, we performed total arch replacement for a residual dissecting aortic arch aneurysm and repaired a kinked graft responsible for haemolytic anaemia. Case 4: a 42-year old man underwent total arch replacement. Eighteen months later, we performed descending thoracic aortic replacement. We repaired a portion of the ascending aorta as haemolityc anaemia was induced by kinking of a total arch replacement redundant graft. All the haemolityc anaemia patients were successfully released after surgical reintervention.

  1. Blood flow competition after aortic valve bypass: an evaluation using computational fluid dynamics.

    Science.gov (United States)

    Kawahito, Koji; Kimura, Naoyuki; Komiya, Kenji; Nakamura, Masanori; Misawa, Yoshio

    2017-05-01

    Aortic valve bypass (AVB) (apico-aortic conduit) remains an effective surgical alternative for patients in whom surgical aortic valve replacement or transcatheter aortic valve implantation is not feasible. However, specific complications include thrombus formation, possibly caused by stagnation arising from flow competition between the antegrade and retrograde flow, but this has not been fully investigated. The aim of this study was to analyse flow characteristics after AVB and to elucidate mechanisms of intra-aortic thrombus using computational fluid dynamics (CFD). Flow simulation was performed on data obtained from a 73-year-old postoperative AVB patient. Three-dimensional cine phase-contrast magnetic resonance imaging at 3 Tesla was used to acquire flow data and to set up the simulation. The vascular geometry was reconstructed using computed tomography angiograms. Flow simulations were implemented at various ratios of the flow rate between the ascending aorta and the graft. Results were visualized by streamline and particle tracing. CFD demonstrated stagnation in the ascending aorta-arch when retrograde flow was dominant, indicating that the risk of thrombus formation exists in the ascending arch in cases with severe aortic stenosis and/or poor left ventricular function. Meanwhile, stagnation was observed in the proximal descending aorta when the antegrade and retrograde flow were equivalent, suggesting that the descending aorta is critical when aortic stenosis is not severe. Flow stagnation in the aorta which may cause thrombus was observed when retrograde flow was dominant and antegrade/retrograde flows were equivalent. Our results suggest that anticoagulants might be recommended even in patients who receive biological valves.

  2. Single crossclamp improves 6-month cognitive outcome in high-risk coronary bypass patients: the effect of reduced aortic manipulation.

    Science.gov (United States)

    Hammon, John W; Stump, David A; Butterworth, John F; Moody, Dixon M; Rorie, Kashemi; Deal, Dwight D; Kincaid, Edward H; Oaks, Timothy E; Kon, Neal D

    2006-01-01

    We hypothesized that a strategy that reduced aortic manipulation would reduce the incidence of cognitive deficits in patients undergoing coronary artery bypass grafting compared with the "traditional" approach and that neurobehavioral outcomes with the reduced aortic manipulation strategy would approach those obtained with off-pump coronary artery bypass surgery. Consenting high-risk patients (those with older age, diabetes, or hypertension) scheduled for coronary artery bypass grafting and cardiopulmonary bypass were randomly assigned to 1 of 2 aortic management protocols: (1) a traditional approach in which distal anastomoses were accomplished while the aorta was crossclamped but in which proximal anastomoses were sewn while a partial occlusion clamp was applied to the aorta (multiple aortic clamping group) or (2) a reduced aortic manipulation approach in which the aorta was clamped a single time with a reduced-pressure clamp (single aortic clamping group) and the partial occlusion clamp was not used. A contemporaneous group of patients undergoing off-pump coronary artery bypass surgery without cardiopulmonary bypass was also enrolled. Subjects in all 3 groups underwent neurologic and neuropsychological testing before and after surgery. After randomization, patients assigned to either approach could be changed to another strategy if the attending surgeon determined that patient safety demanded this change. The study design anticipated that surgical techniques would evolve over the course of patient enrollment and anticipated that some patients would have intraoperative echocardiographic findings that would demand that the traditional approach (eg, severe aortic atherosclerosis) or the reduced manipulation protocol (eg, severe ischemia or poor left ventricular function) be abandoned. Thus, an unequal distribution of patients was expected. By surgeon decision, 20 of 84 multiple aortic clamping patients crossed over to single aortic clamping, and 3 of 85 single

  3. The stable stiffness triangle - drained sand during deformation cycles

    DEFF Research Database (Denmark)

    Sabaliauskas, Tomas; Ibsen, Lars Bo

    2017-01-01

    Cyclic, drained sand stiffness was observed using the Danish triaxial appa- ratus. New, deformation dependant soil property (the stable stiffness triangle) was detected. Using the the stable stiffness triangle, secant stiffness of drained sand was plausible to predict (and control) even during...

  4. Regional variation in aortic AT1b receptor mRNA abundance is associated with contractility but unrelated to atherosclerosis and aortic aneurysms.

    Directory of Open Access Journals (Sweden)

    Aruna Poduri

    Full Text Available Angiotensin II (AngII, the main bioactive peptide of the renin angiotensin system, exerts most of its biological actions through stimulation of AngII type 1 (AT1 receptors. This receptor is expressed as 2 structurally similar subtypes in rodents, termed AT1a and AT1b. Although AT1a receptors have been studied comprehensively, roles of AT1b receptors in the aorta have not been defined.We initially compared the regional distribution of AT1b receptor mRNA with AT1a receptor mRNA in the aorta. mRNA abundance of both subtypes increased from the proximal to the distal aorta, with the greatest abundance in the infra-renal region. Corresponding to the high mRNA abundance for both receptors, only aortic rings from the infra-renal aorta contracted in response to AngII stimulation. Despite the presence of both receptor transcripts, deletion of AT1b receptors, but not AT1a receptors, diminished AngII-induced contractility. To determine whether absence of AT1b receptors influenced aortic pathologies, we bred AT1b receptor deficient mice into an LDL receptor deficient background. Mice were fed a diet enriched in saturated fat and infused with AngII (1,000 ng/kg/min. Parameters that could influence development of aortic pathologies, including systolic blood pressure and plasma cholesterol concentrations, were not impacted by AT1b receptor deficiency. Absence of AT1b receptors also had no effect on size of aortic atherosclerotic lesions and aortic aneurysms in both the ascending and abdominal regions.Regional abundance of AT1b receptor mRNA coincided with AngII-induced regional contractility, but it was not associated with AngII-induced aortic pathologies.

  5. Aortic biomechanics by magnetic resonance: early markers of aortic disease in Marfan syndrome regardless of aortic dilatation?

    Science.gov (United States)

    Teixido-Tura, Gisela; Redheuil, Alban; Rodríguez-Palomares, Jose; Gutiérrez, Laura; Sánchez, Violeta; Forteza, Alberto; Lima, Joao A C; García-Dorado, David; Evangelista, Artur

    2014-01-15

    Previous studies demonstrated the usefulness of MRI in the evaluation of aortic biomechanics in Marfan patients with aortic dilatation. However, these parameters have not been well studied in earlier stages of aortic disease. The present work aimed to study aortic biomechanics: aortic distensibility (AD) and pulse wave velocity (PWV), by MRI in Marfan patients without advanced aortic disease. Eighty consecutive Marfan patients were compared with 36 age- and sex-matched controls. MRI images at the level of ascending, descending and abdominal aorta were used to determine AD and PWV. Marfan patients (27 men; age: 32.0 ± 10.5 years; mean aortic root diameter: 37.2 ± 4.6mm) had lower AD at all levels (ascending 2.6 ± 2.1 vs. 6.2 ± 3.7 mm Hg(-1)·10(-3), pbiomechanics compared with controls. Z-score for ascending ADbiomechanics by MRI were abnormal in the entire aorta in Marfan patients. Moreover, Marfan patients without dilated aortic root showed clear impairment of aortic biomechanics, which suggests that they may be used as early markers of aortic involvement in these patients. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  6. Blood pressure and arterial stiffness in obese children and adolescents.

    Science.gov (United States)

    Hvidt, Kristian Nebelin

    2015-03-01

    Obesity, elevated blood pressure (BP) and arterial stiffness are risk factors for cardiovascular disease. A strong relationship exists between obesity and elevated BP in both children and adults. Obesity and elevated BP in childhood track into adult life increasing the risk of cardiovascular disease in adulthood. Ambulatory BP is the most precise measure to evaluate the BP burden, whereas carotid-femoral pulse wave velocity (cfPWV) is regarded as the gold standard for evaluating arterial (i.e. aortic) stiffness. These measures might contribute to a better understanding of obesity's adverse impact on the cardiovascular system, and ultimately a better prevention and treatment of childhood obesity. The overall aim of the present PhD thesis is to investigate arterial stiffness and 24-hour BP in obese children and adolescents, and evaluate whether these measures are influenced by weight reduction. The present PhD thesis is based on four scientific papers.  In a cross-sectional design, 104 severe obese children and adolescents with an age of 10-18 years were recruited when newly referred to the Children's Obesity Clinic, Holbæk University Hospital, and compared to 50 normal weighted age and gender matched control individuals. Ambulatory BP was measured, and cfPWV was investigated in two ways in respect to the distance measure of aorta; the previously recommended length - the so called subtracted distance, and the currently recommended length - the direct distance. In a longitudinal design, the obese patients were re-investigated after one-year of lifestyle intervention at the Children's Obesity Clinic in purpose of reducing the degree of obesity. In the cross-sectional design, the obese group had higher measures of obesity, while matched for age, gender and height, when compared to the control group. In the longitudinal design, 74% of the 72 followed up obese patients experienced a significant weight reduction. CfPWV was dependent on the method used to measure the

  7. Decellularized aortic homografts for aortic valve and aorta ascendens replacement.

    Science.gov (United States)

    Tudorache, Igor; Horke, Alexander; Cebotari, Serghei; Sarikouch, Samir; Boethig, Dietmar; Breymann, Thomas; Beerbaum, Philipp; Bertram, Harald; Westhoff-Bleck, Mechthild; Theodoridis, Karolina; Bobylev, Dmitry; Cheptanaru, Eduard; Ciubotaru, Anatol; Haverich, Axel

    2016-07-01

    The choice of valve prosthesis for aortic valve replacement (AVR) in young patients is challenging. Decellularized pulmonary homografts (DPHs) have shown excellent results in pulmonary position. Here, we report our early clinical results using decellularized aortic valve homografts (DAHs) for AVR in children and mainly young adults. This prospective observational study included all 69 patients (44 males) operated from February 2008 to September 2015, with a mean age of 19.7 ± 14.6 years (range 0.2-65.3 years). In 18 patients, a long DAH was used for simultaneous replacement of a dilated ascending aorta as an extended aortic root replacement (EARR). Four patients received simultaneous pulmonary valve replacement with DPH. Thirty-nine patients (57%) had a total of 62 previous operations. The mean aortic cross-clamp time in isolated cases was 129 ± 41 min. There was 1 conduit-unrelated death. The mean DAH diameter was 22.4 ± 3.7 mm (range, 10-29 mm), the average peak gradient was 14 ± 15 mmHg and the mean aortic regurgitation grade (0.5 = trace, 1 = mild) was 0.6 ± 0.5. The mean effective orifice area (EOA) of 25 mm diameter DAH was 3.07 ± 0.7 cm(2). DAH annulus z-values were 1.1 ± 1.1 at implantation and 0.7 ± 1.3 at the last follow-up. The last mean left ventricle ejection fraction and left ventricle end diastolic volume index was 63 ± 7% and 78 ± 16 ml/m(2) body surface area, respectively. To date, no dilatation has been observed at any level of the graft during follow-up; however, the observational time is short (140.4 years in total, mean 2.0 ± 1.8 years, maximum 7.6 years). One small DAH (10 mm at implantation) had to be explanted due to subvalvular stenosis and developing regurgitation after 4.5 years and was replaced with a 17 mm DAH without complication. No calcification of the explanted graft was noticed intraoperatively and after histological analysis, which revealed extensive recellularization without inflammation. DAHs withstand systemic

  8. Deficient Circumferential Growth Is the Primary Determinant of Aortic Obstruction Attributable to Partial Elastin Deficiency.

    Science.gov (United States)

    Jiao, Yang; Li, Guangxin; Korneva, Arina; Caulk, Alexander W; Qin, Lingfeng; Bersi, Matthew R; Li, Qingle; Li, Wei; Mecham, Robert P; Humphrey, Jay D; Tellides, George

    2017-05-01

    Williams syndrome is characterized by obstructive aortopathy attributable to heterozygous loss of ELN, the gene encoding elastin. Lesions are thought to result primarily from excessive smooth muscle cell (SMC) proliferation and consequent medial expansion, although an initially smaller caliber and increased stiffness of the aorta may contribute to luminal narrowing. The relative contributions of such abnormalities to the obstructive phenotype had not been defined. We quantified determinants of luminal stenosis in thoracic aortas of Eln-/- mice incompletely rescued by human ELN. Moderate obstruction was largely because of deficient circumferential growth, most prominently of ascending segments, despite increased axial growth. Medial thickening was evident in these smaller diameter elastin-deficient aortas, with medial area similar to that of larger diameter control aortas. There was no difference in cross-sectional SMC number between mutant and wild-type genotypes at multiple stages of postnatal development. Decreased elastin content was associated with medial fibrosis and reduced aortic distensibility because of increased structural stiffness but preserved material stiffness. Elastin-deficient SMCs exhibited greater contractile-to-proliferative phenotypic modulation in vitro than in vivo. We confirmed increased medial collagen without evidence of increased medial area or SMC number in a small ascending aorta with thickened media of a Williams syndrome subject. Deficient circumferential growth is the predominant mechanism for moderate obstructive aortic disease resulting from partial elastin deficiency. Our findings suggest that diverse aortic manifestations in Williams syndrome result from graded elastin content, and SMC hyperplasia causing medial expansion requires additional elastin loss superimposed on ELN haploinsufficiency. © 2017 American Heart Association, Inc.

  9. Development of a Stiffness-Angle Law for Simplifying the Measurement of Human Hair Stiffness.

    Science.gov (United States)

    Jung, I K; Park, S C; Lee, Y R; Bin, S A; Hong, Y D; Eun, D; Lee, J H; Roh, Y S; Kim, B M

    2018-01-25

    This research examines the benefits of caffeine absorption on hair stiffness. In order to test hair stiffness, we have developed an evaluation method that is not only accurate, but also inexpensive. Our evaluation method for measuring hair stiffness culminated in a model, called the Stiffness-Angle Law, which describes the elastic properties of hair and can be widely applied to the development of hair care products. Small molecules (≤ 500 g/mol) such as caffeine can be absorbed into hair. A common shampoo containing 4% caffeine was formulated and applied to hair 10 times, after which the hair stiffness was measured. The caffeine absorption of the treated hair was observed using Fourier Transform Infrared Spectroscopy (FTIR) with a Focal Plane Array (FPA) detector. Our evaluation method for measuring hair stiffness consists of a regular camera and a support for single strands of hair. After attaching the hair to the support, the bending angle of the hair was observed with a camera and measured. Then the hair strand was weighed. The stiffness of the hair was calculated based on our proposed Stiffness-Angle law using three variables: angle, weight of hair, and the distance the hair was pulled across the support. The caffeine absorption was confirmed by FTIR analysis. The concentration of amide bond in the hair certainly increased due to caffeine absorption. After caffeine was absorbed into the hair, the bending angle and weight of the hair changed. Applying these measured changes to the Stiffness-Angle law, it was confirmed that the hair stiffness increased by 13.2% due to caffeine absorption. The theoretical results using the Stiffness-Angle law agree with the visual examinations of hair exposed to caffeine, and also the known results of hair stiffness from a previous report. Our evaluation method combined with our proposed Stiffness-Angle Law effectively provides an accurate and inexpensive evaluation technique for measuring bending stiffness of human hair. This

  10. Aortic root geometry in aortic stenosis patients (a SEAS substudy)

    DEFF Research Database (Denmark)

    Bahlmann, Edda; Nienaber, Christoph A; Cramariuc, Dana

    2011-01-01

    -specified requirements for the aortic root geometry for current available prostheses, CoreValve and Edwards-Sapien. The ratio of sinus of Valsalva height to sinus width was 1:2. In multivariate linear regression analysis, larger sinus of Valsalva height was associated with older age, larger sinus of Valsalva diameter...... with asymptomatic AS (mean age 67 years, 39% women) in the Simvastatin Ezetimibe in AS study were used. The inner aortic diameter was measured at four levels: annulus, sinus of Valsalva, sinotubular junction and supracoronary, and sinus height as the annulo-junctional distance. Analyses were based on vendor......, lower ejection fraction and smaller supracoronary diameter (multiple R(2) = 0.19, P

  11. Measurement of effective aortic valve area using three-dimensional echocardiography in children undergoing aortic balloon valvuloplasty for aortic stenosis.

    Science.gov (United States)

    Bharucha, Tara; Fernandes, Fernanda; Slorach, Cameron; Mertens, Luc; Friedberg, Mark Kevin

    2012-04-01

    Pressure gradient is used for timing of balloon aortic valvuloplasty for aortic stenosis (AS) in children, but does not correlate well with outcome and is limited if ventricular function is poor. In adults, effective orifice area (EOA) is used to assess AS severity, but EOA by continuity equation or 2D echo is unreliable in children. Three-dimensional echocardiography (3DE) may reliably assess EOA but has not been studied in children. We assessed measurement of aortic valve EOA by 3DE in children with AS before and after balloon aortic valvuloplasty and compared results with change in aortic valve gradient. 3DE was performed at time of catheterization before and after balloon aortic valvuloplasty. Using 3DE multiplanar review mode, valve annulus diameter, area, and EOA were measured and compared with change in aortic gradient and degree of aortic insufficiency. Twenty-four 3DE studies in 12 children (mean age 4.4 ± 5.0 years) were analyzed. EOA was measurable in all. Catheter peak gradient decreased from 45 ± 10 to 26 ± 17 mmHg (P = 0.0018). 3DE EOA increased after balloon aortic valvuloplasty (0.59 ± 0.52 cm(2) vs 0.80 ± 0.70 cm(2) ; P = 0.03), without change in valve diameter. EOA change correlated with change in peak (r = 0.77; P = 0.005) and mean (r = 0.60; P = 0.03) aortic valve gradient post balloon aortic valvuloplasty. 3DE facilitates EOA measurement in pediatric AS and correlates with change in aortic valve gradient after balloon valvuloplasty. © 2011, Wiley Periodicals, Inc.

  12. Arterial wall stiffness in patients with essential hypertension at young age

    Directory of Open Access Journals (Sweden)

    Kolesnik E.L.

    2014-11-01

    Full Text Available Research objective was investigating arterial wall stiffness in patients with hypertension at young age and assessing the relationship between subclinical target organs damage and ambulatory blood pressure monitoring (ABPM parameters. 30 male patients aged 18-35 years with essential hypertension stage I and II, hypertension 1 and 2nd grade were surveyed. The examination included general clinical methods, echocardiography, ABPM and suprasystolic sfigmography. It was found that the pulse wave velocity (PWVao (r = 0,557 p <0,01, central aortic blood pressure (SBPao (r = 0,492 p <0,01 and augmentation index (AIxao (r = 0,489 p <0.01 significantly increased with the pa¬tients’ age. Abdominal obesity (r = 0,566 p <0,01 and BMI (r = 0,599 p <0,01 impacted on the PWVao acceleration. Increasing of the left ventricular mass index (LVMI is highly associated with SBPao (r = 0,506 p <0,05 and PWVao (r = 0,434 p <0,05. According to ABPM the most significant correlation with arterial wall stiffness parameters demon¬strated diastolic blood pressure (DBP daytime level (AIxao (r = 0,418 p <0,01, with PWVao (r = 0,699 p <0.01 and SBPao (r = 0,695 p <0,01. Thus, age, excessive body weight and obesity should be considered as unfavorable factors that worsen arterial wall stiffness in patients with hypertension at the age before 35 years. Increase of DBP levels especially during the day causes maximum negative impact on the arterial wall stiffness parameters according to ABPM. Increased SBPao and PWVao in patients with hypertension at a young age are associated with increased left ventricular mass index.

  13. Plant fibre composites - porosity and stiffness

    DEFF Research Database (Denmark)

    Madsen, Bo; Thygesen, Anders; Lilholt, Hans

    2009-01-01

    Plant fibre composites contain typically a relatively large amount of porosity which influences their performance. A model, based on a modified rule of mixtures, is presented to include the influence of porosity on the composite stiffness. The model integrates the volumetric composition...... of the composites with their mechanical properties. The fibre weight fraction is used as an independent parameter to calculate the complete volumetric composition. A maximum obtainable stiffness of the composites is calculated at a certain transition fibre weight fraction, which is characterised by a best possible...... combination of high fibre volume fraction and low porosity. The model is validated with experimental data from the literature on several types of composites. A stiffness diagram is presented to demonstrate that the calculations can be used for tailoring and design of composites with a given profile...

  14. Electrochemical stiffness in lithium-ion batteries

    Science.gov (United States)

    Tavassol, Hadi; Jones, Elizabeth M. C.; Sottos, Nancy R.; Gewirth, Andrew A.

    2016-11-01

    Although lithium-ion batteries are ubiquitous in portable electronics, increased charge rate and discharge power are required for more demanding applications such as electric vehicles. The high-rate exchange of lithium ions required for more power and faster charging generates significant stresses and strains in the electrodes that ultimately lead to performance degradation. To date, electrochemically induced stresses and strains in battery electrodes have been studied only individually. Here, a new technique is developed to probe the chemomechanical response of electrodes by calculating the electrochemical stiffness via coordinated in situ stress and strain measurements. We show that dramatic changes in electrochemical stiffness occur due to the formation of different graphite-lithium intercalation compounds during cycling. Our analysis reveals that stress scales proportionally with the lithiation/delithiation rate and strain scales proportionally with capacity (and inversely with rate). Electrochemical stiffness measurements provide new insights into the origin of rate-dependent chemomechanical degradation and the evaluation of advanced battery electrodes.

  15. Central aortic blood pressure, augmentation index, and reflected wave transit time: reproducibility and repeatability of data obtained by oscillometry

    Directory of Open Access Journals (Sweden)

    Ageenkova O

    2011-11-01

    Full Text Available Olga A Ageenkova, Marina A Purygina Department of Therapy, Functional and Ultrasound Diagnostics, Postgraduate Training Faculty of Smolensk State Medical Academy, Smolensk, Russian Federation Background: The evidence suggests that arterial stiffness acts as an independent predictor of general as well as cardiovascular mortality, strokes in patients with arterial hypertension, type 2 diabetes mellitus in the elderly, and in the general population. The oscillometric method measures parameters of arterial stiffness by applying special methods of processing oscillograms. This is a study of the reproducibility and repeatability of central aortic systolic blood pressure (SBP, augmentation index, and reflected wave transit time measured by Vasotens® technology. Methods: Anthropometric and hemodynamic measurements for 90 volunteers were made by two observers using the 24-hour blood pressure monitoring system, BPLab®, with Vasotens technology in "office" mode, over a period of two days and always at the same time in the morning. Initialization of the device was performed prior to each measurement cycle for each participant. Results: Analysis of short-term repeatability and reproducibility data for central aortic systolic blood pressure, reflected wave transit time, and augmentation index did not reveal any statistically significant differences. For observer A, SBP was 0.11 ± 7.53 mmHg and aortic SBP was 0.26 ± 6.11 mmHg; for observer B, SBP was 0.14 ± 8.42 and aortic SBP was 0.2 ± 7.25 mmHg. Short-term reproducibility for the different observers with averaging of both measurements was 0.36 ± 5.69 mmHg for SBP and 0.37 ± 6.7 mmHg for aortic SBP; the next day, repeatability for observer A was 0.52 ± 10.7 mmHg for SBP and 0.73 ± 8.98 mmHg for aortic SBP. Conclusion: BPLab with Vasotens technology has good reproducibility and repeatability, and can be recommended for clinical vascular risk estimation. Keywords: arterial stiffness, central aortic

  16. Indexing aortic valve area by body surface area increases the prevalence of severe aortic stenosis

    DEFF Research Database (Denmark)

    Jander, Nikolaus; Gohlke-Bärwolf, Christa; Bahlmann, Edda

    2014-01-01

    To account for differences in body size in patients with aortic stenosis, aortic valve area (AVA) is divided by body surface area (BSA) to calculate indexed AVA (AVAindex). Cut-off values for severe stenosis are...

  17. Interruption of the aortic arch, ventricular septal defect, aortic atresia and aortopulmonary fistulous communication.

    Science.gov (United States)

    De Caro, E; Pongiglione, G; Ribaldone, D

    1998-06-01

    Interruption of the aortic arch in association with aortic atresia is a rare condition. We report the second case in literature in which survival was provided by an aortopulmonary fistulous communication.

  18. Assessment and feasibility of the four landmarks of the aortic root in a cohort of very preterm infants

    Science.gov (United States)

    Phillips, Sam; de Waal, Koert A

    2015-01-01

    Background: The diameter of the aortic root is used as a parameter to calculate blood flow in very preterm infants. There are considerable differences in diameter of the four anatomical landmarks of the aortic root in children and adults, but limited data are available for the very preterm population. The aim of this study was to obtain reference and reliability data on two-dimensional measurements of the aortic root in very preterm infants <30 weeks gestation. Materials and Methods: Fifty long axis echocardiograms were reviewed and re-analyzed for measurements at the four anatomical landmarks of the aortic root; the aortic annulus, sinus of Valsalva (SV), sinotubular junction, and the proximal ascending aorta (PAA). A subjective visual scoring system was developed to quantify image quality. A random sample of images was blindly re-measured to assess intra- and inter-observer reliability. Results: Significant differences in diameter were found between the four landmarks, except between SV and PAA. Inter-observer coefficients showed marginal variation ranging from 5.0% to 8.2%, with slightly lower intra-observer variability. Overall image quality score was poorest for PAA on standard long axis images but improved when the probe was adjusted along the outflow tract. Conclusion: We present reliability and reference values for all four anatomic landmarks of the aortic root in very preterm infants and demonstrated the importance of standardizing and reporting cardiac output measurements in preterm infants. PMID:26556963

  19. Transcatheter aortic valve implantation in degenerative sutureless perceval aortic bioprosthesis.

    Science.gov (United States)

    Landes, Uri; Sagie, Alexander; Kornowski, Ran

    2016-10-03

    Sutureless aortic bioprostheses (SAB) are increasingly being used to provide shorter cross-clamp time. Valve-in-valve transcatheter aortic valve replacement (VIV-A) is shown to be effective and safe in the vast majority of patients with degenerated bioprosthetics, yet its' use in SAB failure is infrequent. We present a case of balloon-expandable VIV-A in an 80-year-old woman who suffered severe symptomatic aortic regurgitation in a failed Perceval S 21-mm valve. Computed tomography scan demonstrated a deformed valve. Our heart team favored a percutaneous VIV-A over reoperation due to the patients' high surgical risk. An Edwards-Sapien XT 23 mm was successfully deployed with excellent results. The patient remained asymptomatic following 6 months. As other bioprosthesis, some sutureless valves are condemned to structural valve degeneration. Because VIV-A is being established for managing degenerative bioprosthesis in high risk patients, it is cardinal to identify its role in novel degenerative sutureless valves. SAB were introduced to the clinical market only 5-7 years ago. The absence of sutures may theoretically impose risk for valve instability when adding a transcatheter sutureless valve inside the first one. Our successful experience was very reassuring. We report its feasibility because we believe it should provide support for further investigation on VIV-A within novel SAV. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  20. Elastic stiffness of a Skyrmion crystal.

    Science.gov (United States)

    Nii, Y; Kikkawa, A; Taguchi, Y; Tokura, Y; Iwasa, Y

    2014-12-31

    We observe the elastic stiffness and ultrasonic absorption of a Skyrmion crystal in the chiral-lattice magnet MnSi. The Skyrmion crystal lattice exhibits a stiffness 3 orders of magnitude smaller than that of the atomic lattice of MnSi, being as soft as the flux line lattice in type-II superconductors. The observed anisotropic elastic responses are consistent with the cylindrical shape of the Skyrmion spin texture. Phenomenological analysis reveals that the spin-orbit coupling is responsible for the emergence of anisotropic elasticity in the Skyrmion lattice.

  1. Aortic Calcification: An Early Sign of Heart Valve Problems?

    Science.gov (United States)

    ... the aortic valve — a condition called aortic valve stenosis. Aortic valve calcification may be an early sign ... have any other heart disease symptoms. Calcification and stenosis generally affects people older than age 65. When ...

  2. Genetics Home Reference: familial thoracic aortic aneurysm and dissection

    Science.gov (United States)

    ... a bulge in the blood vessel wall (an aneurysm ). Aortic dilatation may also lead to a sudden tearing of the layers in the aorta wall ( aortic dissection ), allowing blood to flow abnormally between the layers. These aortic abnormalities are ...

  3. Endovascular "neobranching" to manage acute aortic syndrome.

    Science.gov (United States)

    Vandormael, Isabelle L; Salmasi, Mohammad Y; Yeh, James S-M; Nienaber, Christoph A

    2017-08-01

    Acute aortic syndrome was coined in 2001 to describe a spectrum of acute aortic wall pathologies. The syndrome represents a cluster of aortic conditions such as aortic dissection, intramural hematoma and penetrating atherosclerotic ulcer. Acute aortic dissection is more common than the latter two pathologies with an incidence of up to 6 cases per 100,000 per year. The following report focuses on an unusual case presentation emphasizing the newest management techniques including "neobranching" whilst dealing with challenging patient anatomy and refractory hypertension. We believe this case report eventually broadens our understanding of acute aortic syndrome whilst addressing an entry tear outside the aorta by placing "neobranches". © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  4. An in vitro phantom study on the influence of tear size and configuration on the hemodynamics of the lumina in chronic type B aortic dissections.

    Science.gov (United States)

    Rudenick, Paula A; Bijnens, Bart H; García-Dorado, David; Evangelista, Arturo

    2013-02-01

    Management and follow-up of chronic aortic dissections continue to be a clinical challenge due to progressive dilatation and subsequent rupture. To predict complications, guidelines suggest follow-up of aortic diameter. However, dilatation is triggered by hemodynamic parameters (pressures/wall shear stresses) and geometry of false (FL) and true lumen (TL), information not captured by diameter alone. Therefore, we aimed at better understanding the influence of dissection anatomy on TL and FL hemodynamics. In vitro studies were performed using pulsatile flow in realistic dissected latex/silicone geometries with varying tear number, size, and location. We assessed three different conformations: (1) proximal tear only; (2) distal tear only; (3) both proximal and distal tears. All possible combinations (n = 8) of small (10% of aortic diameter) and large (25% of aortic diameter) tears were considered. Pressure, velocity, and flow patterns were analyzed within the lumina (at proximal and distal sections) and at the tears. We also computed the FL mean pressure index (FPI(mean)%) as a percentage of the TL mean pressure, to compare pressures among models. The presence of large tears equalized FL/TL pressures compared with models with only small tears (proximal FPI(mean)% 99.85 ± 0.45 vs 92.73 ± 3.63; distal FPI(mean)% 99.51 ± 0.80 vs 96.35 ± 1.96; P 290 cm/s), and a well-defined flow. Additionally, both proximal and distal tears act as entry and exit. During systole, flow enters the FL through all tears simultaneously, while during diastole, flow leaves through all communications. Flow through the FL, from proximal to distal tears or vice versa, is minimal. Our results suggest that FL hemodynamics heavily depends on cumulative tear size, and thus, it is an important parameter to take into account when clinically assessing chronic aortic dissections. Copyright © 2013 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

  5. Fractures of the proximal humerus

    DEFF Research Database (Denmark)

    Brorson, Stig

    2013-01-01

    . The bandages were further supported by splints made of wood or coarse grass. Healing was expected in forty days. Different fracture patterns have been discussed and classified since Ancient Greece. Current classification of proximal humeral fractures mainly relies on the classifications proposed by Charles......, classification of proximal humeral fractures remains a challenge for the conduct, reporting, and interpretation of clinical trials. The evidence for the benefits of surgery in complex fractures of the proximal humerus is weak. In three systematic reviews I studied the outcome after locking plate osteosynthesis......Fractures of the proximal humerus have been diagnosed and managed since the earliest known surgical texts. For more than four millennia the preferred treatment was forceful traction, closed reduction, and immobilization with linen soaked in combinations of oil, honey, alum, wine, or cerate...

  6. The future of aortic surgery in Europe

    DEFF Research Database (Denmark)

    Czerny, Martin; Bachet, Jean; Bavaria, Joseph

    2012-01-01

    the interested reader with an overview of how aortic surgery and (perhaps more accurately) aortic medicine has evolved in Europe, and its present standing; also to provide a glimpse into the future, trying to disseminate the thoughts of a group of people actively involved in the development of aortic medicine...... in Europe, namely the Vascular Domain of the European Association of Cardio-Thoracic Surgery (EACTS)....

  7. The Efficacy of Autologous Femoropopliteal Vein Reconstruction for Primary Aortic and Aortic Graft Infection

    NARCIS (Netherlands)

    Dirven, M.; Jagt, M.F.P. van der; Barendregt, W.B.; Vliet, D. van der

    2015-01-01

    BACKGROUND: The objective of our study was to analyze the efficacy of autologous superficial femoropopliteal vein reconstruction for primary aortic or aortic graft infection. METHODS: We performed a retrospective analysis of 14 patients treated for an infected aortic prosthesis or primary infected

  8. Transcatheter valve-in-valve implantation due to severe aortic regurgitation in a degenerated aortic homograft

    DEFF Research Database (Denmark)

    Olsen, Lene Kjaer; Engstrøm, Thomas; Søndergaard, Lars

    2009-01-01

    a successful valve-in-valve implantation of a CoreValve aortic valve prosthesis through the right subclavian artery in a case of severe aortic regurgitation within a degenerated aortic homograft. The case exemplifies the possibilities of expanding the indications for TAVI, as well as other vascular access...

  9. Cervical aortic arch and a new type of double aortic arch. Report of a case.

    Science.gov (United States)

    Cornali, M; Reginato, E; Azzolina, G

    1976-09-01

    A case of cervical aortic arch is reported. To the best of our knowledge, it is the first to be associated with a serious intracardiac anomaly. In addition, it is part of a new type of double aortic arch, caused by failure of reabsorption of both dorsal aortic roots and persistence of the fourth right and second (or third) left branchial arches.

  10. Histopathology of aortic complications in bicuspid aortic valve versus Marfan syndrome: relevance for therapy?

    NARCIS (Netherlands)

    N. Grewal (Nimrat); R. Franken (Romy); B.J.M. Mulder (Barbara); M.-J. Goumans (Marie-José); J.H.N. Lindeman (Johannes); M.R.M. Jongbloed (Monique); M.C. DeRuiter (Marco); R.J.M. Klautz (Robert); A.J.J.C. Bogers (Ad); R.E. Poelmann (Robert); A.C.G.-D. Groot (Adriana C. Gittenberger-de)

    2016-01-01

    textabstractPatients with bicuspid aortic valve (BAV) and patients with Marfan syndrome (MFS) are more prone to develop aortic dilation and dissection compared to persons with a tricuspid aortic valve (TAV). To elucidate potential common and distinct pathways of clinical relevance, we compared the

  11. Increased aortic tortuosity indicates a more severe aortic phenotype in adults with Marfan syndrome

    NARCIS (Netherlands)

    Franken, R.; Morabit, A. El; Waard, V. de; Timmermans, J.; Scholte, A.J.; Berg, M.P.; Marquering, H.; Planken, N.R.; Zwinderman, A.H.; Mulder, B.J.; Groenink, M.

    2015-01-01

    BACKGROUND: Patients with Marfan syndrome (MFS) have a highly variable occurrence of aortic complications. Aortic tortuosity is often present in MFS and may help to identify patients at risk for aortic complications. METHODS: 3D-visualization of the total aorta by MR imaging was performed in 211

  12. The infrastructure of psychological proximity

    DEFF Research Database (Denmark)

    Nickelsen, Niels Christian Mossfeldt

    2015-01-01

    ). The experience of psychological proximity between patient and nurse is provided through confidence, continuity and the practical set-up. This constitutes an important enactment of skillfulness, which may render telemedicine a convincing health service in the future. Methodology: The study draws on a pilot...... (Langstrup & Winthereik 2008). This study contributes by showing the infrastructure of psychological proximity, which is provided by way of device, confidence, continuity and accountability....

  13. Type Ia endoleaks after fenestrated and branched endografts may lead to component instability and increased aortic mortality.

    Science.gov (United States)

    O'Callaghan, Adrian; Greenberg, Roy K; Eagleton, Matthew J; Bena, James; Mastracci, Tara Marie

    2015-04-01

    Fenestrated and branched endografts allow for proximal sealing zone extension into or above the visceral aorta to optimize landing in healthy aorta. We describe the incidence, causes, and implications of proximal endoleak development in patients undergoing complex endovascular aortic aneurysm repair. All patients undergoing a fenestrated/branched repair were entered onto a prospective database, and this analysis included all those with at least one postoperative contrast computed tomography scan. Preoperative and postoperative three-dimensional imaging was reanalyzed to characterize morphology and identify endoleak. A blinded assessor used the preoperative imaging to resize the repairs in the endoleak group and a matched cohort of patients without endoleak. The outcome measures were proximal endoleak development, mortality, and component stability, and a comparison was made with all patients undergoing complex aortic repair. From 2001 to July 2013, 969 patients underwent repair in a physician-sponsored investigational device exemption trial. Excluded were 24 emergency patients and 21 patients without requisite imaging, leaving 924 available for analysis. A proximal type Ia endoleak developed in 26 patients (2.8%). Poor choice of landing zone was implicated in most cases, with an area of sealing in the visceral aorta, compared with the thoracic aorta, being significantly associated with endoleak development (P < .01). Aortic-related mortality was significantly higher in the endoleak group (26.9%) than in the group without endoleak (6.2%; P = .001). These patients also experienced a higher incidence of component instability of 30.8% compared with 9.6% in patients without type Ia endoleak (P < .01). Fenestrated/branched endovascular repair has a low incidence of sealing zone failure despite the increased complexity. However, development of a proximal endoleak destabilizes the repair and leads to increased mortality. Increasing complexity of design seems to improve

  14. Hybrid treatment of penetrating aortic ulcer

    Energy Technology Data Exchange (ETDEWEB)

    Lara, Juan Antonio Herrero; Martins-Romeo, Daniela de Araujo; Escudero, Carlos Caparros; Falcon, Maria del Carmen Prieto; Batista, Vinicius Bianchi, E-mail: jaherrero5@hotmail.com [Unidade de Gestao Clinica (UGC) de Diagnostico por Imagem - Hosppital Universitario Virgen Macarena, Sevilha (Spain); Vazquez, Rosa Maria Lepe [Unit of Radiodiagnosis - Hospital Nuestra Senora de la Merced, Osuna, Sevilha (Spain)

    2015-05-15

    Penetrating atherosclerotic aortic ulcer is a rare entity with poor prognosis in the setting of acute aortic syndrome. In the literature, cases like the present one, located in the aortic arch, starting with chest pain and evolving with dysphonia, are even rarer. The present report emphasizes the role played by computed tomography in the diagnosis of penetrating atherosclerotic ulcer as well as in the differentiation of this condition from other acute aortic syndromes. Additionally, the authors describe a new therapeutic approach represented by a hybrid endovascular surgical procedure for treatment of the disease. (author)

  15. [Double aortic arch: prenatal case report].

    Science.gov (United States)

    Budziszewska, Patrycja; Kuka, Dorota; Sodowski, Marcin; Sodowski, Krzysztof; Jeanty, Philippe; Skrzypulec, Violetta

    2009-09-01

    We have presented a case of prenatal double aortic arch, diagnosed by ultrasound, to demonstrate the importance of 3-vessel view by detecting aortic arch abnormalities. Double aortic arch is one the most common types of the vascular ring. The suspicion of a double aortic arch is raised by detecting the U-sign which is formed by the combination of both aortic arches and the left ductus arteriosus. In the 3-vessel view the ascending aorta and aortic arch are pointing to the right, whereas the left arch points to the left, and the trachea is seen between. The 4-chamber view appears normal, but the descending aorta is deviated medially. Literature review revealed an association between double aortic arch and congenital heart diseases in approximately 20% of cases; most often tetralogy of Fallot, transposition of great vessels, ventricular septal defects. Rarely there can be atresia of the segment of the aortic arch, which can be difficult to differentiate from other aortic arch anomalies associated with chromosomal abnormalities such as microdeletion of chromosome 22q11.

  16. Coronary Artery Ectasia Are Frequently Observed in Patients With Bicuspid Aortic Valves With and Without Dilatation of the Ascending Aorta.

    Science.gov (United States)

    Meindl, Christine; Achatz, Birgit; Huber, Deborah; Baessler, Andrea; Hubauer, Ute; Meisinger, Christa; Hengstenberg, Christian; Erdmann, Jeanette; Buchner, Stefan; Maier, Lars; Schunkert, Heribert; Debl, Kurt; Fischer, Marcus

    2016-10-01

    The presence of coronary artery ectasia (CAE) is influenced by genetic factors and related to the presence of aneurysms in other vascular beds. Bicuspid aortic valve (BAV) disease is frequently accompanied by ascending aortic aneurysm. Because the aortic valve and the proximal parts of the coronary arteries share a common embryonic origin, we hypothesized that CAE is associated with BAV disease. One hundred seventy-seven patients with suspected aortic valve disease (n=94 BAV, n=83 tricuspid aortic valve) underwent both cardiac magnetic resonance imaging and coronary angiography. To confirm the association of CAE with BAV, the frequency of CAE was evaluated in an in-house BAV registry (n=600, n=231 with available coronary angiogram) and compared with the frequency of CAE in the German Myocardial Infarction (MI) Family Study, in which the heritability of CAE was formerly established (n=899). Furthermore, the frequency of CAE was investigated in an observational registry of real-life patients undergoing coronary angiography for clinically indicated reasons (n=3.097) and in a subgroup of the KORA MI study (Cooperative Health Research in the Region of Augsburg), which is a population-based MI registry (n=403).Compared with tricuspid aortic valve disease, CAE occurred more than twice as frequently in cardiac magnetic resonance-confirmed BAV disease (17% versus 44%; P<0.0001) and CAE was observed similarly often in subjects with BAV with (37%) and without (54%, P=0.11) ascending aortic pathology. The common appearance of CAE in patients with BAV could be independently confirmed in the BAV registry (frequency 37%), whereas CAE was found less frequently in family history of positive MI patients (21%), sporadic MI without familial disposition (10%), and rarely in unrelated real-life catheterization patients (6%). To our knowledge, our data show for the first time that ectatic coronary artery disease is a common appearance of BAV disease with and without ascending aortic

  17. Impaired Muscle Oxygenation and Elevated Exercise Blood Pressure in Hypertensive Patients: Links With Vascular Stiffness.

    Science.gov (United States)

    Dipla, Konstantina; Triantafyllou, Areti; Koletsos, Nikolaos; Papadopoulos, Stavros; Sachpekidis, Vasileios; Vrabas, Ioannis S; Gkaliagkousi, Eugenia; Zafeiridis, Andreas; Douma, Stella

    2017-08-01

    This study examined in vivo (1) skeletal muscle oxygenation and microvascular function, at rest and during handgrip exercise, and (2) their association with macrovascular function and exercise blood pressure (BP), in newly diagnosed, never-treated patients with hypertension and normotensive individuals. Ninety-one individuals (51 hypertensives and 40 normotensives) underwent office and 24-hour ambulatory BP, arterial stiffness, and central aortic BP assessment, followed by a 5-minute arterial occlusion and a 3-minute submaximal handgrip exercise. Changes in muscle oxygenated and deoxygenated hemoglobin and tissue oxygen saturation were continuously monitored by near-infrared spectroscopy and beat-by-beat BP by Finapres. Hypertensives had higher (Pexercising at the same submaximal intensity, hypertensives required a significantly greater (Pexercise. © 2017 American Heart Association, Inc.

  18. Detonation capturing for stiff combustion chemistry

    NARCIS (Netherlands)

    Berkenbosch, A.C.; Kaasschieter, E.F.; Klein, R.

    1998-01-01

    This paper contributes to the topic of unphysical one-cell-per-time-step travelling combustion wave solutions in numerical computations of detonation waves in the presence of stiff chemical source terms. These false weak detonation solutions appear when a gas-dynamics-chemistry operator-splitting

  19. Alcohol consumption and arterial stiffness in men

    NARCIS (Netherlands)

    Sierksma, A.; Muller, M.; Schouw, Y.T. van der; Grobbee, D.E.; Hendriks, H.F.J.; Bots, M.L.

    2004-01-01

    Objective: Moderate alcohol consumption has been proposed to be anti-atherogenic and protect against coronary heart disease. Arterial stiffness provides a summary measure of atherosclerotic arterial damage and cardiovascular risk. A vascular protective effect of moderate alcohol consumption would be

  20. Bipedal walking gait with variable stiffness knees

    NARCIS (Netherlands)

    Roozing, W.; Carloni, Raffaella

    The Segmented Spring-Loaded Inverted Pendulum model is analysed, and it is shown that it exhibits walking gait. We propose a control architecture that exploits control of the knee stiffness to provide robustness of the system with respect to changes in gait. This controller is extended for a

  1. Robust Bipedal Walking with Variable Leg Stiffness

    NARCIS (Netherlands)

    Visser, L.C.; Stramigioli, Stefano; Carloni, Raffaella

    The bipedal spring-mass model embodies important characteristics of human walking, and therefore serves as an important starting point in studying human-like walking for robots. In this paper, we propose to extend the bipedal spring-mass model with variable leg stiffness and exploit the potential of

  2. Aortic root disease in athletes: aortic root dilation, anomalous coronary artery, bicuspid aortic valve, and Marfan's syndrome.

    Science.gov (United States)

    Yim, Eugene Sun

    2013-08-01

    Two professional athletes in the U.S. National Basketball Association required surgery for aortic root dilation in 2012. These cases have attracted attention in sports medicine to the importance of aortic root disease in athletes. In addition to aortic root dilation, other forms of aortic disease include anomalous coronary artery, bicuspid aortic valve, and Marfan's syndrome. In this review, electronic database literature searches were performed using the terms "aortic root" and "athletes." The literature search produced 122 manuscripts. Of these, 22 were on aortic root dilation, 21 on anomalous coronary arteries, 12 on bicuspid aortic valves, and 8 on Marfan's syndrome. Aortic root dilation is a condition involving pathologic dilation of the aortic root, which can lead to life-threatening sequelae. Prevalence of the condition among athletes and higher risk athletes in particular sports needs to be better delineated. Normative parameters for aortic root diameter in the general population are proportionate to anthropomorphic variables, but this has not been validated for athletes at the extremes of anthropomorphic indices. Although echocardiography is the favored screening modality, computed tomography (CT) and cardiac magnetic resonance imaging (MRI) are also used for diagnosis and surgical planning. Medical management has utilized beta-blockers, with more recent use of angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), and statins. Indications for surgery are based on comorbidities, degree of dilation, and rate of progression. Management decisions for aortic root dilation in athletes are nuanced and will benefit from the development of evidence-based guidelines. Anomalous coronary artery is another form of aortic disease with relevance in athletes. Diagnosis has traditionally been through cardiac catheterization, but more recently has included evaluation with echocardiography, multislice CT, and MRI. Athletes with this

  3. Early results of valve-sparing ascending aortic replacement in type A aortic dissection and aortic insufficiency

    Directory of Open Access Journals (Sweden)

    М. Л. Гордеев

    2016-08-01

    Full Text Available Aim: The study was designed to investigate predictors of effective valve-sparing ascending aortic replacement in patients with Stanford type A aortic dissection combined with aortic insufficiency and to analyze efficacy and safety of this kind of surgery.Methods: From January 2010 to December 2015, 49 patients with Stanford type A aortic dissection combined with aortic insufficiency underwent ascending aortic replacement. All patients were divided into 3 groups: valve-sparing procedures (group 1, n = 11, combined aortic valve and supracoronary ascending aortic replacement (group 2, n = 12, and Bentall procedure (group 3, n = 26. We assessed the initial status of patients, incidence of complications and efficacy of valve-sparing ascending aortic replacement.Results: The hospital mortality rate was 8.2% (4/49 patients. The amount of surgical correction correlated with the initial diameter of the aorta at the level of the sinuses of Valsalva. During the hospital period, none of patients from group 1 developed aortic insufficiency exceeding Grade 2 and the vast majority of patients had trivial aortic regurgitation. The parameters of cardiopulmonary bypass, cross-clamp time and circulatory arrest time did not correlate with the initial size of the ascending aorta and aortic valve blood flow impairment, neither did they influence significantly the incidence and severity of neurological complications. The baseline size of the ascending aorta and degree of aortic regurgitation did not impact the course of the early hospital period.Conclusions: Supracoronary ascending aortic replacement combined with aortic valve repair in ascending aortic dissection and aortic regurgitation is effective and safe. The initial size of the ascending aorta and aortic arch do not influence immediate results. The diameter of the aorta at the level of the sinuses of Valsalva and the condition of aortic valve leaflets could be considered as the limiting factors. Further long

  4. Altered arterial stiffness and subendocardial viability ratio in young healthy light smokers after acute exercise.

    Directory of Open Access Journals (Sweden)

    Robert J Doonan

    Full Text Available Studies showed that long-standing smokers have stiffer arteries at rest. However, the effect of smoking on the ability of the vascular system to respond to increased demands (physical stress has not been studied. The purpose of this study was to estimate the effect of smoking on arterial stiffness and subendocardial viability ratio, at rest and after acute exercise in young healthy individuals.Healthy light smokers (n = 24, pack-years = 2.9 and non-smokers (n = 53 underwent pulse wave analysis and carotid-femoral pulse wave velocity measurements at rest, and 2, 5, 10, and 15 minutes following an exercise test to exhaustion. Smokers were tested, 1 after 12h abstinence from smoking (chronic condition and 2 immediately after smoking one cigarette (acute condition. At rest, chronic smokers had higher augmentation index and lower aortic pulse pressure than non-smokers, while subendocardial viability ratio was not significantly different. Acute smoking increased resting augmentation index and decreased subendocardial viability ratio compared with non-smokers, and decreased subendocardial viability ratio compared with the chronic condition. After exercise, subendocardial viability ratio was lower, and augmentation index and aortic pulse pressure were higher in non-smokers than smokers in the chronic and acute conditions. cfPWV rate of recovery of was greater in non-smokers than chronic smokers after exercise. Non-smokers were also able to achieve higher workloads than smokers in both conditions.Chronic and acute smoking appears to diminish the vascular response to physical stress. This can be seen as an impaired 'vascular reserve' or a blunted ability of the blood vessels to accommodate the changes required to achieve higher workloads. These changes were noted before changes in arterial stiffness or subendocardial viability ratio occurred at rest. Even light smoking in young healthy individuals appears to have harmful effects on vascular

  5. Altered arterial stiffness and subendocardial viability ratio in young healthy light smokers after acute exercise.

    Science.gov (United States)

    Doonan, Robert J; Scheffler, Patrick; Yu, Alice; Egiziano, Giordano; Mutter, Andrew; Bacon, Simon; Carli, Franco; Daskalopoulos, Marios E; Daskalopoulou, Stella S

    2011-01-01

    Studies showed that long-standing smokers have stiffer arteries at rest. However, the effect of smoking on the ability of the vascular system to respond to increased demands (physical stress) has not been studied. The purpose of this study was to estimate the effect of smoking on arterial stiffness and subendocardial viability ratio, at rest and after acute exercise in young healthy individuals. Healthy light smokers (n = 24, pack-years = 2.9) and non-smokers (n = 53) underwent pulse wave analysis and carotid-femoral pulse wave velocity measurements at rest, and 2, 5, 10, and 15 minutes following an exercise test to exhaustion. Smokers were tested, 1) after 12h abstinence from smoking (chronic condition) and 2) immediately after smoking one cigarette (acute condition). At rest, chronic smokers had higher augmentation index and lower aortic pulse pressure than non-smokers, while subendocardial viability ratio was not significantly different. Acute smoking increased resting augmentation index and decreased subendocardial viability ratio compared with non-smokers, and decreased subendocardial viability ratio compared with the chronic condition. After exercise, subendocardial viability ratio was lower, and augmentation index and aortic pulse pressure were higher in non-smokers than smokers in the chronic and acute conditions. cfPWV rate of recovery of was greater in non-smokers than chronic smokers after exercise. Non-smokers were also able to achieve higher workloads than smokers in both conditions. Chronic and acute smoking appears to diminish the vascular response to physical stress. This can be seen as an impaired 'vascular reserve' or a blunted ability of the blood vessels to accommodate the changes required to achieve higher workloads. These changes were noted before changes in arterial stiffness or subendocardial viability ratio occurred at rest. Even light smoking in young healthy individuals appears to have harmful effects on vascular function

  6. Full metal jacket: transfemoral aortic valve implantation for regurgitant valve after endovascular aortic repair†.

    Science.gov (United States)

    Tanyeli, Omer; Dereli, Yuksel; Gormus, Niyazi; Duzenli, Mehmet Akif

    2017-07-25

    Transfemoral aortic valve implantation has become an almost routine interventional procedure for severe aortic stenosis in high-risk patients. Over time an increased number of experiences has led to unusual procedures. In this report, we present a successful valve-in-valve transfemoral aortic valve implantation in a patient with aortic regurgitation, who previously had debranching and thoracic endovascular aortic repair operations. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  7. Stiff person syndrome in South Asia.

    Science.gov (United States)

    Chang, Thashi; Lang, Bethan; Vincent, Angela

    2016-10-18

    Stiff person syndrome is a highly disabling, progressive autoimmune disorder of the central nervous system characterized by muscle rigidity and spasms. Stiff person syndrome is rare, but is believed to be under diagnosed with only 14 cases been reported among a 1.7 billion population in South Asia. We report the first authenticated case from Sri Lanka. A 55-year-old Sri Lankan female presented with difficulty in walking and recurrent falls due to progressive muscular rigidity in her lower limbs and trunk with superimposed muscle spasms that occurred in response to unexpected noise, startle or emotional upset. She had anxiety and specific phobias to open spaces, walking unaided and being among crowds of people. She had insulin-dependent diabetes mellitus and was on thyroxine replacement. On examination, she had hyperlordosis combined with board-like rigidity of her anterior abdomen and rigidity of her lower limbs bilaterally. Upper limbs were normal. Magnetic resonance imaging of her neuraxis was normal. Electromyography showed continuous motor unit activity at rest. Glutamic acid decarboxylase antibodies were detected in her serum at a titre of 15,500 IU/ml (normal <5). She showed a remarkable and sustained improvement to treatment with intravenous immunoglobulins, immunosuppressive and muscle relaxant medications, regaining independent ambulation. Diagnosis of stiff person syndrome remains clinical, supported by electromyography and serology for glutamic acid decarboxylase antibodies, facilitated by a high index of clinical suspicion. An autoimmune basis lends stiff person syndrome amenable to treatment highlighting the importance of diagnosis. This case adds to map the worldwide distribution of stiff person syndrome.

  8. Successful resuscitation from two cardiac arrests in a female patient with critical aortic stenosis, severe mitral regurgitation and coronary artery disease

    Directory of Open Access Journals (Sweden)

    Mijušković Dragan

    2012-01-01

    Full Text Available Introduction. The incidence of sudden cardiac death in patients with severe symptomatic aortic stenosis is up to 34% and resuscitation is described as highly unsuccessful. Case report. A 72-year-old female patient with severe aortic stenosis combined with severe mitral regurgitation and three-vessel coronary artery disease was successfully resuscitated following two in-hospital cardiac arrests. The first cardiac arrest occurred immediately after intraarterial injection of low osmolar iodinated agent during coronary angiography. Angiography revealed 90% occlusion of the proximal left main coronary artery and circumflex branch. The second arrest followed induction of anesthesia. Following successful open-chest resuscitation, aortic valve replacement, mitral valvuloplasty and three-vessel aortocoronary bypass were performed. Postoperative pericardial tamponade required surgical revision. The patient recovered completely. Conclusion. Decision to start resuscitation may be justified in selected patients with critical aortic stenosis, even though cardiopulmonary resuscitation in such cases is generally considered futile.

  9. Modification of an endovascular stent graft for abdominal aortic aneurysm

    Science.gov (United States)

    Moloye, Olajompo Busola

    Endovascular surgery is currently used to treat abdominal aortic aneurysms (AAA). A stent graft is deployed to exclude blood flow from the aneurysm sac. It is an effective procedure used in preventing aneurysm rupture, with reduced patient morbidity and mortality compared to open surgical repair. Migration and leakage around the device ("endoleak") due to poor sealing of the stent graft to the aorta have raised concerns about the long-term durability of endovascular repair. A preliminary study of cell migration and proliferation is presented as a prelude to a more extensive in vivo testing. A method to enhance the biological seal between the stent graft and the aorta is proposed to eliminate this problem. This can be achieved by impregnating the stent graft with 50/50 poly (DL-lactide co glycolic acid) (PLGA) and growth factors such as basic fibroblast growth factor (bFGF) or connective tissue growth factor (CTGF), at the proximal and distal ends. It is hypothesized that as PLGA degrades it will release the growth factors that will promote proliferation and migration of aortic smooth muscle cells to the coated site, leading to a natural seal between the aorta and the stent graft. In addition, growth factor release should promote smooth muscle cell (SMC) contraction that will help keep the stent graft in place at the proximal and distal ends. It is shown that a statistically significant effect of increased cell proliferation and migration is observed for CTGF release. Less of an effect is noted for bFGF or just the PLGA. The effect is estimated to be large enough to be clinically significant in a future animal study. The long term goal of this study is to reduce migration encounter after graft deployment and to reduce secondary interventions of EVAR especially for older patients who are unfit for open surgical treatment.

  10. Pregnancy after aortic root replacement in Loeys-Dietz syndrome: High risk of aortic dissection.

    Science.gov (United States)

    Braverman, Alan C; Moon, Marc R; Geraghty, Patrick; Willing, Marcia; Bach, Christopher; Kouchoukos, Nicholas T

    2016-08-01

    Loeys-Dietz syndrome due to mutations in TGFBR1 and 2 is associated with early and aggressive aortic aneurysm and branch vessel disease. There are reports of uncomplicated pregnancy in this condition, but there is an increased risk of aortic dissection and uterine rupture. Women with underlying aortic root aneurysm are cautioned about the risk of pregnancy-related aortic dissection. Prophylactic aortic root replacement is recommended in women with aortopathy and aortic root dilatation to lessen the risk of pregnancy. There is limited information in the literature about the outcomes of pregnancy after root replacement in Loeys-Dietz syndrome. We present a case series of three women with Loeys-Dietz syndrome who underwent elective aortic root replacement for aneurysm disease and subsequently became pregnant and underwent Cesarean section delivery. Each of these women were treated with beta blockers throughout pregnancy. Surveillance echocardiograms and noncontrast MRA studies during pregnancy remained stable demonstrating no evidence for aortic enlargement. Despite the normal aortic imaging and careful observation, two of the three women suffered acute aortic dissection in the postpartum period. These cases highlight the high risk of pregnancy following aortic root replacement in Loeys-Dietz syndrome. Women with this disorder are recommended to be counseled accordingly. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  11. Mitral and aortic regurgitation following transcatheter aortic valve replacement.

    Science.gov (United States)

    Szymański, Piotr; Hryniewiecki, Tomasz; Dąbrowski, Maciej; Sorysz, Danuta; Kochman, Janusz; Jastrzębski, Jan; Kukulski, Tomasz; Zembala, Marian

    2016-05-01

    To analyse the impact of postprocedural mitral regurgitation (MR), in an interaction with aortic regurgitation (AR), on mortality following transcatheter aortic valve implantation (TAVI). To assess the interaction between MR and AR, we compared the survival rate of patients (i) without both significant MR and AR versus (ii) those with either significant MR or significant AR versus (iii) with significant MR and AR, all postprocedure. 381 participants of the Polish Transcatheter Aortic Valve Implantation Registry (166 males (43.6%) and 215 females (56.4%), age 78.8±7.4 years) were analysed. Follow-up was 94.1±96.5 days. In-hospital and midterm mortality were 6.6% and 10.2%, respectively. Significant MR and AR were present in 16% and 8.1% patients, including 3.1% patients with both significant MR and AR. Patients with significant versus insignificant AR differed with respect to mortality (log rank p=0.009). This difference was not apparent in a subgroup of patients without significant MR (log rank p=0.80). In a subgroup of patients without significant AR, there were no significant differences in mortality between individuals with versus without significant MR (log rank p=0.44). Significant MR and AR had a significant impact on mortality only when associated with each other (log rank p<0.0001). At multivariate Cox regression modelling concomitant significant MR and AR were independently associated with mortality (OR 3.2, 95% CI 1.54 to 5.71, p=0.002). Significant MR or AR postprocedure, when isolated, had no impact on survival. Combined MR and AR had a significant impact on a patient's prognosis. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  12. Use of Suture-Mediated Closure Device in Percutaneous Direct Carotid Puncture During Chimney-Thoracic Endovascular Aortic Repair

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Gabriel, E-mail: dr.changabriel@gmail.com; Quek, Lawrence Hwee Han, E-mail: lawrence-quek@ttsh.com.sg [Tan Tock Seng Hospital, Department of Diagnostic Radiology (Singapore); Tan, Glenn Leong Wei, E-mail: glenn-tan@ttsh.com.sg [Tan Tock Seng Hospital, Department of General Surgery (Singapore); Pua, Uei, E-mail: druei@yahoo.com [Tan Tock Seng Hospital, Department of Diagnostic Radiology (Singapore)

    2016-07-15

    BackgroundInsertion of a carotid chimney graft during thoracic endovascular aortic repair (Ch-TEVAR) is a recognized technique to extend the proximal landing zone into the aortic arch in the treatment of thoracic aortic disease. Conventional technique requires surgical exposure of the carotid artery for insertion of the carotid chimney graft.MethodologyWe describe our experience in the use of a suture-mediated closure device in percutaneous Ch-TEVAR in four patients.ResultsSuccessful hemostasis was achieved in all four patients. No complications related to the carotid puncture were recorded.ConclusionWe conclude that using suture-mediated closure device for carotid closure appears feasible and deserves further studies as a potential alternative to conventional surgical approach.

  13. Stiffness analysis and experimental validation of robotic systems

    Science.gov (United States)

    Carbone, Giuseppe

    2011-06-01

    Stiffness can be considered of primary importance in order to guarantee the successful use of any robotic system for a given task. Therefore, this paper proposes procedures for carrying out both numerical and experimental estimations of stiffness performance for multibody robotic systems. The proposed numerical procedure is based on models with lumped parameters for deriving the Cartesian stiffness matrix. Stiffness performance indices are also proposed for comparing stiffness performance. Then, an experimental procedure for the evaluation stiffness performance is proposed as based on a new measuring system named as Milli-CATRASYS (Milli Cassino Tracking System) and on a trilateration technique. Cases of study are reported to show the soundness and engineering feasibility of both the proposed numerical formulation for stiffness analysis and experimental validation of stiffness performance.

  14. Graft infections after surgical aortic reconstructions

    NARCIS (Netherlands)

    Berger, P.

    2015-01-01

    Prosthetic vascular grafts are frequently used to reconstruct (part) of the aorta. Every surgical procedure caries a certain risk for infection and when a prosthetic aortic graft is implanted, this may lead to an aortic graft infection (AGI). Endovascular techniques have gradually replaced open

  15. Spontaneous resolution late after aortic dissection

    NARCIS (Netherlands)

    Zeebregts, CJAM; Schepens, MAAM; Vermeulen, FEE

    A 50-year-old man was operated on for acute type I (DeBakey classification) aortic dissection. The supracoronary ascending aorta was replaced with an interposition graft. Postoperative computed tomography and angiography clearly revealed a double-barrelled aortic arch, left common carotid artery and

  16. Abdominal aortic aneurysm and diastasis recti.

    Science.gov (United States)

    McPhail, Ian

    Midline abdominal incisional hernias are common following open repair of abdominal aortic aneurysms. These may be caused by the weakness of connective tissue. This study sought to determine the prevalence of diastasis recti among unoperated Caucasian males with abdominal aortic aneurysm compared to a control group with atherosclerotic lower extremity peripheral arterial disease. Forty-two consecutive white males referred for evaluation of abdominal aortic aneurysm (n = 18) or peripheral arterial disease (n = 24) were examined by a single examiner at the Mayo Clinic. Both groups were similar in terms of age and smoking history, 2 major risk factors for both abdominal aortic aneurysm and peripheral arterial disease. Abdominal aortic aneurysm patients ranged in age from 59 to 89 (mean, 73.2) years. Seventeen of 18 (94.4%) had a history of smoking. Peripheral arterial disease patients ranged in age from 52 to 93 (mean, 70.8) years. Twenty-one of 24 (87.5%) had a history of smoking. Diastasis recti were present in 12 of 18 (66.7%) subjects with abdominal aortic aneurysm versus 4 of 24 (16.7%) subjects with peripheral arterial disease (P = .001, 2-tailed Fisher exact test). Diastasis recti are significantly more common in males with abdominal aortic aneurysm than peripheral arterial disease and may provide an important clue to screen for abdominal aortic aneurysm in those at risk.

  17. Valve-sparing aortic root replacement†

    NARCIS (Netherlands)

    Koolbergen, David R.; Manshanden, Johan S. J.; Bouma, Berto J.; Blom, Nico A.; Mulder, Barbara J. M.; de Mol, Bas A. J. M.; Hazekamp, Mark G.

    2015-01-01

    To evaluate our results of valve-sparing aortic root replacement and associated (multiple) valve repair. From September 2003 to September 2013, 97 patients had valve-sparing aortic root replacement procedures. Patient records and preoperative, postoperative and recent echocardiograms were reviewed.

  18. Thoracic aortic catastrophes : towards the endovascular solution

    NARCIS (Netherlands)

    Jonker, F.H.W.

    2010-01-01

    Descending thoracic aortic catastrophes include a variety of acute pathologies of the descending thoracic aorta, which are all associated with high morbidity and mortality rates, requiring immediate intervention. For this thesis, we explored the management and outcomes of several thoracic aortic

  19. The passive stiffness of the wrist and forearm

    Science.gov (United States)

    Charles, Steven K.; Zollo, Loredana; Guglielmelli, Eugenio; Hogan, Neville; Krebs, Hermano I.

    2012-01-01

    Because wrist rotation dynamics are dominated by stiffness (Charles SK, Hogan N. J Biomech 44: 614–621, 2011), understanding how humans plan and execute coordinated wrist rotations requires knowledge of the stiffness characteristics of the wrist joint. In the past, the passive stiffness of the wrist joint has been measured in 1 degree of freedom (DOF). Although these 1-DOF measurements inform us of the dynamics the neuromuscular system must overcome to rotate the wrist in pure flexion-extension (FE) or pure radial-ulnar deviation (RUD), the wrist rarely rotates in pure FE or RUD. Instead, understanding natural wrist rotations requires knowledge of wrist stiffness in combinations of FE and RUD. The purpose of this report is to present measurements of passive wrist stiffness throughout the space spanned by FE and RUD. Using a rehabilitation robot designed for the wrist and forearm, we measured the passive stiffness of the wrist joint in 10 subjects in FE, RUD, and combinations. For comparison, we measured the passive stiffness of the forearm (in pronation-supination), as well. Our measurements in pure FE and RUD agreed well with previous 1-DOF measurements. We have linearized the 2-DOF stiffness measurements and present them in the form of stiffness ellipses and as stiffness matrices useful for modeling wrist rotation dynamics. We found that passive wrist stiffness was anisotropic, with greater stiffness in RUD than in FE. We also found that passive wrist stiffness did not align with the anatomical axes of the wrist; the major and minor axes of the stiffness ellipse were rotated with respect to the FE and RUD axes by ∼20°. The direction of least stiffness was between ulnar flexion and radial extension, a direction used in many natural movements (known as the “dart-thrower's motion”), suggesting that the nervous system may take advantage of the direction of least stiffness for common wrist rotations. PMID:22649208

  20. Cubesat Proximity Operations Demonstration (CPOD)

    Science.gov (United States)

    Villa, Marco; Martinez, Andres; Petro, Andrew

    2015-01-01

    The CubeSat Proximity Operations Demonstration (CPOD) project will demonstrate rendezvous, proximity operations and docking (RPOD) using two 3-unit (3U) CubeSats. Each CubeSat is a satellite with the dimensions 4 inches x 4 inches x 13 inches (10 centimeters x 10 centimeters x 33 centimeters) and weighing approximately 11 pounds (5 kilograms). This flight demonstration will validate and characterize many new miniature low-power proximity operations technologies applicable to future missions. This mission will advance the state of the art in nanosatellite attitude determination,navigation and control systems, in addition to demonstrating relative navigation capabilities.The two CPOD satellites are scheduled to be launched together to low-Earth orbit no earlier than Dec. 1, 2015.

  1. Increased burden and severity of metabolic syndrome and arterial stiffness in treatment naïve HIV+ patients from Cameroon

    Directory of Open Access Journals (Sweden)

    Ngatchou W

    2013-09-01

    Full Text Available William Ngatchou,1 Daniel Lemogoum,1 Pierre Ndobo,2,† Euloge Yagnigni,2 Emiline Tiogou,2 Elisabeth Nga,2 Charles Kouanfack,2 Philippe van de Borne,1 Michel P Hermans3 1Hypertension Clinic, Erasme University Hospital, Brussels, Belgium; 2Department of Cardiology, Central Hospital, Yaoundé, Cameroon; 3Department of Endocrinology and Nutrition, Cliniques Universitaires St-Luc, Brussels, Belgium †Professor Pierre Ndobo passed away on January 21, 2013 Background: Human immunodeficiency virus (HIV and its therapy are associated with increased aortic stiffness and metabolic syndrome (MetS phenotype in Caucasian patients. We hypothesized that, independently of antiretroviral therapy, HIV infection in native black African patients is associated with increased burden of cardiometabolic risk factors that may accelerate arterial structural damage and translate into increased aortic stiffness. Patients and methods: Ninety-six apparently healthy Cameroonian subjects (controls were compared to 108 untreated Cameroonian HIV+ patients (HIV-UT of similar age. In each participant, pulse wave velocity (Complior, aortic augmentation index (SphygmoCor, brachial blood pressure (Omron 705 IT, fasting plasma glucose (FPG, and lipids were recorded, as well as the prevalence and severity of MetS, based on the American Heart Association/National Heart, Lung, and Blood Institute score ≥3/5. Results: Prevalence of impaired fasting glucose (FPG 100–125 mg · dL-1 and of diabetes (FPG > 125 mg · dL-1 was higher in HIV-UT than in controls (47% versus 27%, and 26% versus 1%, respectively; both P < 0.01. Fasting triglycerides and the atherogenic dyslipidemia ratio were significantly higher in HIV-UT than in controls. Hypertension prevalence was high and comparable in both groups (41% versus 44%, respectively; not significant. HIV-UT patients exhibited a twice-higher prevalence of MetS than controls (47% versus 21%; P = 0.02. Age- and sex-adjusted pulse wave velocity was

  2. Correlates of Osteoprotegerin and Association with Aortic Pulse Wave Velocity in Patients with Chronic Kidney Disease

    Science.gov (United States)

    Leonard, Mary B.; Townsend, Raymond R.; Appel, Lawrence; Wolf, Myles; Budoff, Matt J.; Chen, Jing; Lustigova, Eva; Gadegbeku, Crystal A.; Glenn, Melanie; Hanish, Asaf; Raj, Dominic; Rosas, Sylvia E.; Seliger, Stephen L.; Weir, Matthew R.; Parekh, Rulan S.

    2011-01-01

    Summary Background and objectives Osteoprotegerin (OPG), a cytokine that regulates bone resorption, has been implicated in the process of vascular calcification and stiffness. Design, setting, participants, & measurements Serum OPG was measured in 351 participants with chronic kidney disease (CKD) from one site of the Chronic Renal Insufficiency Cohort Study. Cortical bone mineral content (BMC) was measured by quantitative computed tomography in the tibia. Multivariable linear regression was used to test the association between serum OPG and traditional cardiovascular risk factors, measures of abnormal bone and mineral metabolism, and pulse wave velocity. Results Higher serum OPG levels were associated with older age, female gender, greater systolic BP, lower estimated GFR, and lower serum albumin. OPG was not associated with measures of abnormal bone or mineral metabolism including serum phosphorus, albumin-corrected serum calcium, intact parathyroid hormone, bone-specific alkaline phosphatase, or cortical BMC. Among 226 participants with concurrent aortic pulse wave velocity measurements, increasing tertiles of serum OPG were associated with higher aortic pulse wave velocity after adjustment for demographics, traditional vascular risk factors, and nontraditional risk factors such as estimated GFR, albuminuria, serum phosphate, corrected serum calcium, presence of secondary hyperparathyroidism, serum albumin, and C-reactive protein or after additional adjustment for cortical BMC in a subset (n = 161). Conclusions These data support a strong relationship between serum OPG and arterial stiffness independent of many potential confounders including traditional cardiovascular risk factors, abnormal bone and mineral metabolism, and inflammation. PMID:21940840

  3. A novel method of measuring passive quasi-stiffness in the first metatarsophalangeal joint

    Directory of Open Access Journals (Sweden)

    Marabelle L. Heng

    2016-10-01

    Full Text Available Abstract Background First metatarsophalangeal joint (MTPJ mobility is commonly assessed by its angular displacement (joint angle or subjectively rated as ‘hypermobile’, ‘normal’ or ‘stiff’ by a clinician. Neither of these methods is ideal because displacement alone does not take into account the force required to displace the joint and subjective evaluation is not always reliable. This study presented a novel method to determine the passive quasi-stiffness of the first MTPJ. The reliability of the proposed method was also assessed. The first MTPJ passive quasi-stiffness of 13 healthy subjects were measured at two occasions, 7 days apart, by two testers (experienced and inexperienced. A tactile pressure sensing system was used to measure the force applied to dorsiflex the first toe by the testers. The torque (in Nmm about the first MTPJ was calculated as the applied force (in N multiplied by a moment arm (in mm, where moment arm was the length of the first proximal phalanx. A video camera recorded the motion of the first MTPJ, simultaneously with force measurements, to determine the joint angular displacement (in degrees using the Dartfish software. The quasi-stiffness (in Nmm/degrees was calculated as the slope of a graph where torque was plotted against first MTPJ angular displacement. Descriptive statistics of the first MTPJ quasi-stiffness were calculated. Intra-rater and inter-rater reliability were assessed using Bland and Altman plot, intraclass correlation coefficients (ICC, and standard error of measurement (SEM. Results First MTPJ quasi-stiffness of the subjects ranged widely from 0.66 to 53.4 Nmm/degrees. Intra-rater reliability for experienced tester was moderate (Session 1: 14.9 ± 14.6 Nmm/degrees, Session 2: 14.2 ± 8.5 Nmm/degrees, ICC = .568, SEM = 7.71 Nmm/degrees. Inter-rater reliability between experienced (12.6 ± 8.4 Nmm/degrees and non-experienced (19.9 ± 9.2 Nmm/degrees testers was

  4. How Crouch Gait Can Dynamically Induce Stiff-Knee Gait

    NARCIS (Netherlands)

    Van der Krogt, M.M.; Bregman, D.J.J.; Wisse, M.; Doorenbosch, C.A.M.; Harlaar, J.; Collins, S.H.

    Children with cerebral palsy frequently experience foot dragging and tripping during walking due to a lack of adequate knee flexion in swing (stiff-knee gait). Stiff-knee gait is often accompanied by an overly flexed knee during stance (crouch gait). Studies on stiff-knee gait have mostly focused on

  5. How Crouch Gait Can Dynamically Induce Stiff-Knee Gait

    NARCIS (Netherlands)

    van der Krogt, M.M.; Bregman, D.J.J.; Wisse, M.; Doorenbosch, C.A.M.; Harlaar, J.

    2010-01-01

    Children with cerebral palsy frequently experience foot dragging and tripping during walking due to a lack of adequate knee flexion in swing (stiff-knee gait). Stiff-knee gait is often accompanied by an overly flexed knee during stance (crouch gait). Studies on stiff-knee gait have mostly focused on

  6. A 2-DOF joint with coupled variable output stiffness

    NARCIS (Netherlands)

    Tan, Daniel J.; Brouwer, Dannis Michel; Fumagalli, Matteo; Carloni, Raffaella

    This paper presents a 2-degree-of-freedom (DOF) joint with coupled variable output stiffness that makes use of three actuators, i.e., two for the 2-D joint motions and one for the joint stiffness adjustment. By base-mounting the actuators and the variable stiffness module that contains the passive

  7. Aortic elasticity and carotid intima-media thickness in children with mitral valve prolapse.

    Science.gov (United States)

    Erolu, Elif; Akalın, Figen; Çetiner, Nilüfer; Şaylan Çevik, Berna

    2017-11-07

    Aim We aimed to study the dimensions, systolic and diastolic functions of the left ventricle; dimensions and elasticity of the aorta; and carotid intima-media thickness and flow-mediated dilatation of the brachial artery in mitral valve prolapse. The study group consisted of 43 patients (mean age=13.3±3.9) and 42 healthy children (mean age=12.9±3.4). Left ventricular end-diastolic, end-systolic, left atrial diameters, interventricular septum, and left ventricular posterior wall thickness were measured. Ejection and shortening fractions were calculated by M-mode. Measurements were adjusted to the body surface area. Mitral annulus, and systolic and diastolic diameters of the aortic annulus and aorta at each level were obtained; z-scores, aortic strain, distensibility, stiffness index were calculated. Carotid intima-media thickness and flow-mediated dilatation were studied. Patients were classified as classical/non-classical mitral valve prolapse and younger/older patients. Left ventricular end-systolic, end-diastolic, and left atrial diameters (p=0.009, p=0.024, p=0.001) and aortic z-scores at annulus, sinus valsalva, and sinotubuler junction were larger (p=0.008, p=0.003, p=0.002, respectively) in the mitral valve prolapse group. Aortic strain and distensibility increased and stiffness decreased at the ascending aorta in the patient group (p=0.012, 0.020, p=0.019, respectively). Classical mitral valve prolapse had lower strain and distensibility and higher stiffness of the aorta at sinus valsalva level (p=0.010, 0.027, 0.004, respectively). Carotid intima-media thickness was thinner in the patient group, especially in the non-classical mitral valve prolapse group (p=0.037). Flow-mediated dilatation did not differ among the groups. Mitral valve prolapse is a systemic disease of the connective tissue causing enlarged cardiac chambers and increased elasticity of the aorta. Decreased carotid intima-media thickness in this group may indicate low atherosclerosis risk.

  8. Hypoplastic right cervical aortic arch.

    Science.gov (United States)

    Gerrah, Rabin; Shah, Amee; Langley, Stephen M; Quaegebeur, Jan M

    2012-12-01

    We describe a neonate with a rare congenital anomaly of the aorta. The anomaly included a hypoplastic aortic arch that was cervical and right sided. This complex combination was treated by a Norwood type procedure reconstructing a right-sided arch and, in a later stage, a Rastelli procedure. These 2 procedures achieved a 2 ventricular repair. The diagnostic and surgical challenges of this rare anomaly are described in this case report. Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  9. The progression of aortic aneurysms.

    Science.gov (United States)

    Mastracci, Tara M

    2016-04-01

    Aortic aneurysm is a progressive disease that can involve any territory of the aorta. This has ramifications on endovascular repair, because progressive dilation of sealing zones can compromise the integrity of the repair and lead to long term failure. This article describes the evidence behind and some of the predictors of progressive disease of the aorta. Knowledge of predictors of progressive disease may help prevent it from causing failure in the longterm by helping to tailor surveillance routines or have influence on initial graft design.

  10. FELINE AORTIC THROMBOEMBOLISM: CASE REPORT

    OpenAIRE

    Figueroa A., Lizbeth; Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima, Perú.; Paz M., Ricardo; Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima, Perú.; Díaz C., Diego; Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima, Perú.; Dávila F., Roberto; Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima, Perú.

    2014-01-01

    Se presenta el caso de un felino Siamés de 13 años con tromboembolismo aórtico. Esta es una complicación asociada a una cardiomiopatía hipertrófica (CMH), enfermedad cardiaca más común del gato y que se caracteriza por la hipertrofia concéntrica ventricular izquierda. A case of a 13 year old Siamese cat whit feline aortic thromboembolism is presented. This is a devastating complication associated to hypertrophic cardiomyopathy (HCM), one of the most common heart disease in cats characteriz...

  11. Pathogenic Mechanisms of Bicuspid Aortic Valve Aortopathy

    Science.gov (United States)

    Yassine, Noor M.; Shahram, Jasmine T.; Body, Simon C.

    2017-01-01

    Bicuspid aortic valve (BAV) is the most common congenital valvular defect and is associated with ascending aortic dilation (AAD) in a quarter of patients. AAD has been ascribed both to the hemodynamic consequences of normally functioning and abnormal BAV morphology, and to the effect of rare and common genetic variation upon function of the ascending aortic media. AAD manifests in two overall and sometimes overlapping phenotypes: that of aortic root aneurysm, similar to the AAD of Marfan syndrome; and that of tubular AAD, similar to the AAD seen with tricuspid aortic valves (TAVs). These aortic phenotypes appear to be independent of BAV phenotype, have different embryologic origins and have unique etiologic factors, notably, regarding the role of hemodynamic changes inherent to the BAV phenotype. Further, in contrast to Marfan syndrome, the AAD seen with BAV is infrequently present as a strongly inherited syndromic phenotype; rather, it appears to be a less-penetrant, milder phenotype. Both reduced levels of normally functioning transcriptional proteins and structurally abnormal proteins have been observed in aneurysmal aortic media. We provide evidence that aortic root AAD has a stronger genetic etiology, sometimes related to identified common non-coding fibrillin-1 (FBN1) variants and other aortic wall protein variants in patients with BAV. In patients with BAV having tubular AAD, we propose a stronger hemodynamic influence, but with pathology still based on a functional deficit of the aortic media, of genetic or epigenetic etiology. Although it is an attractive hypothesis to ascribe common mechanisms to BAV and AAD, thus far the genetic etiologies of AAD have not been associated to the genetic etiologies of BAV, notably, not including BAV variants in NOTCH1 and GATA4. PMID:28993736

  12. Endovascular Treatment of Infrarenal Abdominal Aortic Aneurysm with Short and Angulated Neck in High-Risk Patient

    Directory of Open Access Journals (Sweden)

    Stylianos Koutsias

    2013-01-01

    Full Text Available Endovascular treatment of abdominal aortic aneurysms (AAA is an established alternative to open repair. However lifelong surveillance is still required to monitor endograft function and signal the need for secondary interventions (Hobo and Buth 2006. Aortic morphology, especially related to the proximal neck, often complicates the procedure or increases the risk for late device-related complications (Hobo et al. 2007 and Chisci et al. 2009. The definition of a short and angulated neck is based on length (60° (Hobo et al. 2007 and Chisci et al. 2009. A challenging neck also offers difficulties during open repairs (OR, necessitating extensive dissection with juxta- or suprarenal aortic cross-clamping. Patients with extensive aneurysmal disease typically have more comorbidities and may not tolerate extensive surgical trauma (Sarac et al. 2002. It is, therefore, unclear whether aneurysms with a challenging proximal neck should be offered EVAR or OR (Cox et al. 2006, Choke et al. 2006, Robbins et al. 2005, Sternbergh III et al. 2002, Dillavou et al. 2003, and Greenberg et al. 2003. In our case the insertion of a thoracic endograft followed by the placement of a bifurcated aortic endograft for the treatment of a very short and severely angulated neck proved to be feasible offering acceptable duration of aneurysm exclusion. This adds up to our armamentarium in the treatment of high-risk patients, and it should be considered in emergency cases when the fenestrated and branched endografts are not available.

  13. Markers of inflammation, endothelial activation, and arterial stiffness in hypertensive heart disease and the effects of treatment: results from the SILVHIA study.

    Science.gov (United States)

    Jekell, Andreas; Malmqvist, Karin; Wallén, N Håkan; Mörtsell, David; Kahan, Thomas

    2013-12-01

    We assessed the contribution of blood pressure (BP), inflammation, and endothelial activation to the development of structural vascular and cardiac changes in hypertension. Furthermore, the effects of antihypertensive therapy were studied. We studied 114 patients with hypertension and left ventricular hypertrophy and 38 matched hypertensive subjects without cardiac hypertrophy and 38 normotensive subjects. The group with hypertension and cardiac hypertrophy were randomized to treatment with an angiotensin receptor blocker (irbesartan) or a beta-adrenergic receptor blocker (atenolol) for 48 weeks. Markers of inflammation (high-sensitive C-reactive protein, interleukin-6, leukocyte counts), vascular function (ambulatory aortic stiffness index, arterial compliance, and pulse pressure), and endothelial activation (E-selectin, intracellular adhesion molecule-1, vascular adhesion molecule-1) were assessed. Markers of inflammation and arterial stiffness were lowest in the normotensive group and highest in patients with hypertensive heart disease; endothelial markers were similar between groups. Inflammation was independently related to BP. Markers of arterial stiffness were independently related to BP and to a lesser extent to left ventricular mass. Antihypertensive treatment improved arterial compliance; inflammatory and endothelial markers remained unchanged. In conclusion, markers of inflammation and arterial stiffness are independently related to BP. Antihypertensive therapy seems to improve arterial stiffness, but effects on markers of inflammation and endothelial activation are small.

  14. Electrothermally Actuated Microbeams With Varying Stiffness

    KAUST Repository

    Tella, Sherif Adekunle

    2017-11-03

    We present axially loaded clamped-guided microbeams that can be used as resonators and actuators of variable stiffness, actuation, and anchor conditions. The applied axial load is implemented by U-shaped electrothermal actuators stacked at one of the beams edges. These can be configured and wired in various ways, which serve as mechanical stiffness elements that control the operating resonance frequency of the structures and their static displacement. The experimental results have shown considerable increase in the resonance frequency and mid-point deflection of the microbeam upon changing the end conditions of the beam. These results can be promising for applications requiring large deflection and high frequency tunability, such as filters, memory devices, and switches. The experimental results are compared to multi-physics finite-element simulations showing good agreement among them.

  15. Dispersive Stiffness of Dzyaloshinskii Domain Walls

    Science.gov (United States)

    Pellegren, J. P.; Lau, D.; Sokalski, V.

    2017-07-01

    It is well documented that subjecting perpendicular magnetic films that exhibit the interfacial Dzyaloshinskii-Moriya interaction to an in-plane magnetic field results in a domain wall (DW) energy σ , which is highly anisotropic with respect to the orientation of the DW in the film plane Θ . We demonstrate that this anisotropy has a profound impact on the elastic response of the DW as characterized by the surface stiffness σ ˜ (Θ )=σ (Θ )+σ''(Θ ) and evaluate its dependence on the length scale of deformation. The influence of stiffness on DW mobility in the creep regime is assessed, with analytic and numerical calculations showing trends in σ ˜ that better represent experimental measurements of domain wall velocity in magnetic thin films compared to σ alone. Our treatment provides experimental support for theoretical models of the mobility of anisotropic elastic manifolds and makes progress toward a more complete understanding of magnetic domain wall creep.

  16. Plasma Oxidized Low-density Lipoprotein Levels and Arterial Stiffness in Older Adults: the Health ABC Study

    Science.gov (United States)

    Brinkley, Tina E.; Nicklas, Barbara J.; Kanaya, Alka M.; Satterfield, Suzanne; Lakatta, Edward G.; Simonsick, Eleanor M.; Sutton-Tyrrell, Kim; Kritchevsky, Stephen B.

    2009-01-01

    Arterial stiffness is a prominent feature of vascular aging and is strongly related to cardiovascular disease (CVD). Oxidized low-density lipoprotein (ox-LDL), a key player in the pathogenesis of atherosclerosis, may also play a role in arterial stiffening, but this relationship has not been well studied. Thus, we examined the cross-sectional association between ox-LDL and aortic pulse wave velocity (aPWV), a marker of arterial stiffness, in community-dwelling older adults. Plasma ox-LDL levels and aPWV were measured in 2,295 participants (mean age, 74 yrs; 52% female; 40% black) from the Health, Aging and Body Composition study. Mean aPWV significantly increased across tertiles of ox-LDL (tertile 1, 869 ± 376 cm/s; tertile 2, 901 ± 394 cm/s; tertile 3, 938 ± 415 cm/s; p=0.002). In multivariate analyses, ox-LDL remained associated with aPWV after adjustment for demographics and traditional CVD risk factors (p=0.008). After further adjustment for hemoglobin A1c, abdominal visceral fat, anti-hypertensive and antilipemic medications, and CRP the association with ox-LDL was attenuated, but remained significant (p=0.01). Results were similar when ox-LDL was expressed in absolute (mg/dL) or relative amounts (percent of LDL). Moreover, individuals in the highest ox-LDL tertile were 30-55% more likely to have high arterial stiffness, defined as aPWV > 75th percentile (p≤0.02). In conclusion, we found that among elderly persons, elevated plasma ox-LDL levels are associated with higher arterial stiffness, independent of CVD risk factors. These data suggest that ox-LDL may be related to the pathogenesis of arterial stiffness. PMID:19332658

  17. Open aortic arch surgery in chronic dissection with visceral arteries originating from different lumens.

    Science.gov (United States)

    Urbanski, Paul P; Bougioukakis, Petros; Deja, Marek A; Diegeler, Anno; Irimie, Vadim; Lenos, Aristidis; Zembala, Michal O

    2016-05-01

    Surgical management of chronic aortic dissection is controversial, especially when the dissection extends into the abdominal aorta in which the visceral arteries originate from different lumens and is combined with aortic arch pathology necessitating surgery. The aim of the study was to evaluate the results of open surgery in this complex aortic pathology. Between June 2002 and 2015, a total of 17 patients (median age 57, range 32-76 years) necessitating complete arch replacement presented complex chronic dissection of the thoraco-abdominal aorta with the visceral arteries originating from different lumens. Fourteen patients (82%) had had previous cardiac surgery, which was performed on the proximal aorta in all but one because of acute type A dissection. Nine patients without considerable dilatation of the descending aorta received aortic arch replacement with distal resection of the dissection membrane, and 8 patients with progressive dilatation of the thoracic aorta underwent aortic arch and descending aorta replacement via clamshell approach. No early (defined as 30-day, 90-day and in-hospital period) deaths, strokes or spinal cord injuries occurred. Only 1 patient (6%) presented temporary neurological dysfunctions (delirium, agitation), which resolved completely before discharge, and an injury of the recurrent laryngeal nerve was documented in 2 patients (12%). Temporary dialysis was necessary in 1 case. The follow-up was complete for all patients. All but one patient, who died due to leukaemia 23 months after surgery, were alive at the last follow-up (median duration 33 months, range 2-118 months). No patient needed a reoperation or an intervention on the thoracic and/or abdominal aorta. Moreover, no noticeable progression of the chronic dissection in the downstream aorta was documented in any patient. The results after conventional aortic arch repair with distal resection of the dissection membrane and, if necessary, with replacement of the progressively

  18. Normative Values of Aortic Arch Structures in Premature Infants

    NARCIS (Netherlands)

    Dijkema, Elles J; Molenschot, Mirella C; Breur, JMPJ; de Vries, WB; Slieker, Martijn G

    BACKGROUND: Aortic arch abnormalities represent 5% to 8% of all congenital heart disease. Measurements of the aortic arch dimensions on two-dimensional echocardiographic images remain of critical importance in the diagnosis of aortic arch pathology. To define aortic hypoplasia or coarctation,

  19. Quantitative image analysis for planning of aortic valve replacement

    NARCIS (Netherlands)

    Elattar, M.A.I.M.

    2016-01-01

    Aortic stenosis is the most common and frequent cause of sudden death among all valvular heart diseases. Symptomatic aortic stenosis is considered to be a fatal disease if left untreated. Aortic valve replacement is the mainstay of treatment of symptomatic aortic stenosis. Traditional treatment of

  20. Circulating vascular progenitor cells and central arterial stiffness in polycystic ovary syndrome.

    Directory of Open Access Journals (Sweden)

    Cecile Dessapt-Baradez

    Full Text Available Subjects with Polycystic ovarian syndrome (PCOS are at increased risk of Type 2 diabetes mellitus (T2DM. The mechanism of this enhanced risk is unclear. Circulating vascular progenitor cells (VPC are immature bone marrow derived cells capable of differentiating into mature endothelial cells. VPC number/function and central arterial stiffness predict cardio-metabolic disease in at-risk populations.We studied VPC and arterial stiffness measures in non-obese PCOS subjects as compared to age and body mass index (BMI matched healthy controls in a cross-sectional study.Fourteen subjects with PCOS and 12 controls of similar age, BMI (all <30 kg/m(2 and metabolic profile were studied. VPC number and in vitro function were studied by flow cytometry and tube formation assays respectively. Augmentation index (AIx, a measure of central arterial stiffness, and central (aortic blood pressures (BP were measured by applanation tonometry.Subjects with PCOS had a reduced number, mean±SEM, of circulating CD34(+133(+ VPCs (317.5±51.0 vs. 558.3±101.2, p = 0.03 and impaired in vitro tube formation (completed tube area 1.0±0.06 vs. 1.2±0.05×10(6 µm(2 p = 0.02. PCOS subjects had significantly higher AIx (18.4±1.9% vs. 4.9±2.0% and this difference remained significant even after adjustments for age, BMI and smoking (p = 0.003 in multivariate analyses. Central systolic and pulse pressure were higher in PCOS subjects but these differences were not statistically significant after adjustment for age. Brachial systolic and pulse pressures were similar. VPC number/function and arterial stiffness or BP measures were not correlated.Non-obese PCOS is characterized by a reduced VPC number, impaired VPC function and increased central arterial stiffness. These changes in novel vascular risk markers may explain the enhanced risk of T2DM and CVD in PCOS.

  1. Evaluation of aortic regurgitation after transcatheter aortic valve implantation: aortic root angiography in comparison to cardiac magnetic resonance.

    Science.gov (United States)

    Frick, Michael; Meyer, Christian G; Kirschfink, Annemarie; Altiok, Ertunc; Lehrke, Michael; Brehmer, Kathrin; Lotfi, Shahram; Hoffmann, Rainer

    2016-03-01

    Aortic regurgitation (AR) is common after transcatheter aortic valve implantation (TAVI). Intraprocedural assessment of AR relies on aortic root angiography. Cardiac magnetic resonance (CMR) phase-contrast mapping of the ascending aorta provides accurate AR quantification. This study evaluated the accuracy of AR grading by aortic root angiography after TAVI in comparison to CMR phase-contrast velocity mapping. In 69 patients with TAVI for severe aortic stenosis, post-procedural AR was determined by aortic root angiography with visual assessment according to the Sellers classification and by CMR using phase-contrast velocity mapping for analysis of AR volume and fraction. Spearman's correlation coefficient showed a moderate correlation between angiographic analysis of AR grade and CMR-derived AR volume (r=0.41; pangiography with cut-off Sellers grade ≥2 had a sensitivity of 71% and a specificity of 98% to detect AR graded as moderate to severe or severe as defined by CMR. There is only a moderate correlation between aortic root angiography and CMR in the classification of AR severity after TAVI. Alternative imaging including multimodality imaging as well as haemodynamic analysis should therefore be considered for intraprocedural AR assessment and guidance of TAVI procedure in cases of uncertainty in AR grading.

  2. Small aortic root in aortic valve stenosis: clinical characteristics and prognostic implications.

    Science.gov (United States)

    Bahlmann, Edda; Cramariuc, Dana; Minners, Jan; Lønnebakken, Mai Tone; Ray, Simon; Gohlke-Baerwolf, Christa; Nienaber, Christoph A; Jander, Nikolaus; Seifert, Reinhard; Chambers, John B; Kuck, Karl Heinz; Gerdts, Eva

    2017-04-01

    In aortic valve stenosis (AS), having a small aortic root may influence both the assessment of AS severity and the treatment strategy. The aim was to test the prognostic implications of having a small aortic root in AS within a large prospective study. We used data from 4.3-year follow-up of 1560 patients with asymptomatic, initially mostly moderate AS enrolled in the Simvastatin and Ezetimibe in Aortic Stenosis study. A small aortic root was defined as inner aortic sinotubular junction diameter indexed for body height <1.4 cm/m in women and <1.5 cm/m in men. A small aortic root was found in 270 patients (17.3%) at baseline. Having a small aortic root was associated with larger aortic root wall thickness, higher pressure recovery, lower systemic arterial compliance, left ventricular mass index, and female sex in a multivariable logistic regression analysis (all P < 0.05). In the Cox regression analysis, having a small aortic root at baseline was associated with higher hazard rates of ischaemic cardiovascular events (n = 268; HR 1.55, 95% CI 1.16-2.06), non-haemorrhagic stroke (n = 55; HR 1.88, 95% CI 1.04-3.41), and cardiovascular death (n = 81; HR 2.08, 95% CI 1.28-3.39) (all P < 0.05) after adjusting for confounders, including randomized study treatment, sex, hypertension, AS severity, and aortic valve replacement. In AS patients without known cardiovascular disease or diabetes, having a small aortic root was associated with increased ischaemic cardiovascular events and mortality. The results suggest a relation between the presence of a small aortic root and that of subclinical atherosclerosis. ClinicalTrials.gov identifier: NCT00092677.

  3. The stiffness change and the increase in the ultimate capacity for a stiff pile resulting from a cyclic loading

    DEFF Research Database (Denmark)

    Lada, Aleksandra; Ibsen, Lars Bo; Nicolai, Giulio

    In the paper the experimental results of small-scale tests on a stiff monopile are presented to outline the change in stiffness during the cyclic loading and the change in the ultimate pile capacity. The results confirm the increase of stiffness and the increase in bearing capacity resulting from...

  4. Characterization of the transport topology in patient-specific abdominal aortic aneurysm models

    Science.gov (United States)

    Arzani, Amirhossein; Shadden, Shawn C.

    2012-08-01

    Abdominal aortic aneurysm (AAA) is characterized by disturbed blood flow patterns that are hypothesized to contribute to disease progression. The transport topology in six patient-specific abdominal aortic aneurysms was studied. Velocity data were obtained by image-based computational fluid dynamics modeling, with magnetic resonance imaging providing the necessary simulation parameters. Finite-time Lyapunov exponent (FTLE) fields were computed from the velocity data, and used to identify Lagrangian coherent structures (LCS). The combination of FTLE fields and LCS was used to characterize topological flow features such as separation zones, vortex transport, mixing regions, and flow impingement. These measures offer a novel perspective into AAA flow. It was observed that all aneurysms exhibited coherent vortex formation at the proximal segment of the aneurysm. The evolution of the systolic vortex strongly influences the flow topology in the aneurysm. It was difficult to predict the vortex dynamics from the aneurysm morphology, motivating the application of image-based flow modeling.

  5. The validity of ultrasonographic scanning as screening method for abdominal aortic aneurysms

    DEFF Research Database (Denmark)

    Lindholt, J.S; Vammen, S; Juul, Svend

    1999-01-01

    Objective:the sensitivity and specificity of screening for abdominal aortic aneurysms (AAAs) with ultrasonographic scanning (US) is unknown. The aim of the study was to validate US as screening test for AAAs.Methods and material:4176 (76.3%) of 5470 men aged 65–73 attended hospital-based US...... screening for an AAA at their local hospital. Two observers and one scanner were used. The maximal anterior–posterior (AP) of the dilated aorta, or 2 cm above the bifurcation, and at the crossing of left renal vein was recorded. In 50 cases, blinded measurements were carried out by two observers. An AAA...... for AAA. Screening for proximal infrarenal aorta aneurysm remains acceptable because the majority of aortic diameters in this segment are so much smaller than the diameters that define an AAA....

  6. Determination of muscle effort at the proximal femur rotation osteotomy

    Science.gov (United States)

    Sachenkov, O.; Hasanov, R.; Andreev, P.; Konoplev, Yu

    2016-11-01

    The paper formulates the problem of biomechanics of a new method for treatment of Legg-Calve-Perthes disease. Numerical calculations of the rotational flexion osteotomy have been carried out for a constructed mathematical model of the hip joint, taking into account the main set of muscles. The work presents the results of the calculations and their analysis. The results have been compared with the clinical data. The calculations of the reactive forces arising in the acetabulum and the proximal part of the femur allowed us to reveal that this reactive force changes both in value and direction. These data may be useful for assessing the stiffness of an external fixation device used in orthopedic intervention and for evaluating the compression in the joint.

  7. Complications following dislocations of the proximal interphalangeal joint.

    Science.gov (United States)

    Mangelson, John J; Stern, Peter J; Abzug, Joshua M; Chang, James; Osterman, A Lee

    2014-01-01

    Dorsal fracture-dislocations of the proximal interphalangeal joint are challenging injuries to treat and are associated with many complications. The determination of stability is crucial to appropriate management. Stable injuries can usually be treated nonsurgically, whereas unstable injuries typically require surgical stabilization. Many surgical techniques have been used, including extension block pinning, volar plate arthroplasty, open reduction and internal fixation, external fixation, and hemihamate autografting. Because stiffness and flexion contracture are frequent complications, every effort should be made to initiate early motion while maintaining concentric reduction. Other complications include redislocation, chronic swelling, swan neck and coronal plane deformities, and pin tract infections. Assessing injury characteristics, including chronicity, the percentage of articular surface fractured, and the degree of comminution, and understanding complications will help in determining the most appropriate treatment. Chronic dislocations and those injuries in which painful arthritis develops can be successfully treated with salvage procedures, including arthroplasty and arthrodesis.

  8. SHORT COMMUNICATION PROXIMATE COMPOSITION, MINERAL ...

    African Journals Online (AJOL)

    Preferred Customer

    SHORT COMMUNICATION. PROXIMATE COMPOSITION, MINERAL CONTENT AND ANTINUTRITIONAL. FACTORS OF SOME CAPSICUM (Capsicum annum) VARIETIES GROWN IN. ETHIOPIA. Esayas K.1, Shimelis A.2, Ashebir F.3, Negussie R.3, Tilahun B.4 and Gulelat D.4*. 1Hawassa University, Department of Food ...

  9. Static stiffness modeling of a novel hybrid redundant robot machine

    Energy Technology Data Exchange (ETDEWEB)

    Li Ming, E-mail: hackingming@gmail.com [Laboratory of Intelligent Machines, Lappeenranta University of Technology (Finland); Wu Huapeng; Handroos, Heikki [Laboratory of Intelligent Machines, Lappeenranta University of Technology (Finland)

    2011-10-15

    This paper presents a modeling method to study the stiffness of a hybrid serial-parallel robot IWR (Intersector Welding Robot) for the assembly of ITER vacuum vessel. The stiffness matrix of the basic element in the robot is evaluated using matrix structural analysis (MSA); the stiffness of the parallel mechanism is investigated by taking account of the deformations of both hydraulic limbs and joints; the stiffness of the whole integrated robot is evaluated by employing the virtual joint method and the principle of virtual work. The obtained stiffness model of the hybrid robot is analytical and the deformation results of the robot workspace under certain external load are presented.

  10. Morning pressor surge, blood pressure variability, and arterial stiffness in essential hypertension.

    Science.gov (United States)

    Pucci, Giacomo; Battista, Francesca; Anastasio, Fabio; Schillaci, Giuseppe

    2017-02-01

    An excess morning blood pressure surge (MBPS) may portend an increased cardiovascular risk, but the mechanisms thereof have been little investigated. The link between MBPS, short-term blood pressure (BP) variability, and arterial stiffness has not been entirely defined. In 602 consecutive untreated hypertensive patients (48 ± 12 years, 61% men, office BP 149/93 ± 17/10 mmHg), we measured carotid-femoral pulse wave velocity (cf-PWV, SphygmoCor) and 24-h ambulatory BP. Using self-reported sleep and wake times, MBPS was defined as sleep-trough (ST-MBPS), prewaking, rising. Short-term BP variability was calculated as weighted 24-h SBP SD and average real variability of 24-h SBP (ARV), that is, average of absolute differences between consecutive SBP readings. ST-MBPS (r = 0.16, P < 0.001) and rising MBPS (r = 0.12, P = 0.003) showed a direct correlation with cf-PWV, whereas prewaking MBPS had no such relation (r = 0.06, P = 0.14). Only ST-MBPS was independently associated with cf-PWV (t = 1.96, P = 0.04) after adjustment for age, sex, height, office mean arterial pressure, heart rate, and renal function. This association was lost after further adjustment for weighted 24-h SBP SD (P = 0.13) or ARV (P = 0.24). ARV was a significant mediator of the relationship between ST-MBPS and cf-PWV (P = 0.003). In untreated hypertension, ST-MBPS has a direct relation with aortic stiffness, which is mediated by an increased ARV. The adverse effects of MBPS may be partly explained by its link with arterial stiffness, mediated by short-term SBP variability.

  11. Factors Affecting Optimal Aortic Remodeling After Thoracic Endovascular Aortic Repair of Type B (IIIb) Aortic Dissection

    Energy Technology Data Exchange (ETDEWEB)

    Chen, I-Ming [National Yang Ming University, Institute of Clinical Medicine, School of Medicine (China); Chen, Po-Lin; Huang, Chun-Yang [National Yang Ming University, Department of Medicine, School of Medicine (China); Weng, Shih-Hsien; Chen, Wei-Yuan; Shih, Chun-Che, E-mail: ccshih@vghtpe.gov.tw [National Yang Ming University, Institute of Clinical Medicine, School of Medicine (China)

    2017-05-15

    PurposeThe purpose of this study was to determine factors associated with entire aortic remodeling after thoracic endovascular aortic repair (TEVAR) in patients with type B dissection.Materials and MethodsThe patients with type B (IIIb) dissections who underwent TEVAR from 2006 to 2013 with minimum of 2 years of follow-up computed tomography data were retrospectively reviewed. Based on the status of false lumen remodeling of entire aorta, patients were divided into three groups: complete regression, total thrombosis, and inadequate regression with patent abdominal false lumen.ResultsA total of 90 patients (72 males, 18 females; mean age 56.6 ± 16.4 years) were included and divided into the complete regression (n = 22), total thrombosis (n = 18), and inadequate regression (n = 50) groups. Multivariate logistic regression analysis indicated that dissection extension to iliac arteries, increased preoperative number of dissection tear over abdominal aorta, and decreased preoperative abdominal aorta bifurcation true lumen ratio, as compared between the inadequate and complete regression groups, were associated with a persistent false lumen (odds ratio = 33.33, 2.304, and 0.021; all, p ≤ 0.012). Comparison of 6, 12, and 24 months postoperative data revealed no significant differences at any level, suggesting that the true lumen area ratio might not change after 6 months postoperatively.ConclusionsIncreased preoperative numbers of dissection tear around the abdominal visceral branches, dissection extension to the iliac arteries, and decreased preoperative true lumen area ratio of abdominal aorta are predictive of entire aortic remodeling after TEVAR in patients with type B dissection.Level of EvidenceIII.

  12. Evaluation of arterial stiffness by finger-toe pulse wave velocity: optimization of signal processing and clinical validation.

    Science.gov (United States)

    Obeid, Hasan; Khettab, Hakim; Marais, Louise; Hallab, Magid; Laurent, Stéphane; Boutouyrie, Pierre

    2017-08-01

    Carotid-femoral pulse wave velocity (PWV) (cf-PWV) is the gold standard for measuring aortic stiffness. Finger-toe PWV (ft-PWV) is a simpler noninvasive method for measuring arterial stiffness. Although the validity of the method has been previously assessed, its accuracy can be improved. ft-PWV is determined on the basis of a patented height chart for the distance and the pulse transit time (PTT) between the finger and the toe pulpar arteries signals (ft-PTT). The objective of the first study, performed in 66 patients, was to compare different algorithms (intersecting tangents, maximum of the second derivative, 10% threshold and cross-correlation) for determining the foot of the arterial pulse wave, thus the ft-PTT. The objective of the second study, performed in 101 patients, was to investigate different signal processing chains to improve the concordance of ft-PWV with the gold-standard cf-PWV. Finger-toe PWV (ft-PWV) was calculated using the four algorithms. The best correlations relating ft-PWV and cf-PWV, and relating ft-PTT and carotid-femoral PTT were obtained with the maximum of the second derivative algorithm [PWV: r = 0.56, P signal processing chain. Selecting the maximum of the second derivative algorithm for detecting the foot of the pressure waveform, and combining it with an optimized signal processing chain, improved the accuracy of ft-PWV measurement in the current population sample. Thus, it makes ft-PWV very promising for the simple noninvasive determination of aortic stiffness in clinical practice.

  13. Evaluation of percutaneous pinning in unstable proximal humeral fractures: A novel technique

    Directory of Open Access Journals (Sweden)

    Nishikant Kumar

    2013-01-01

    Full Text Available Management of unstable proximal humeral fractures has remained controversial since ages. Open reduction and internal fixation have resulted in devastating complications like stiffness of shoulder joint, avascular necrosis, infection, etc., We are presenting a novel method of percutaneous pinning of unstable proximal humeral fractures. All cases (32 were done closely without soft tissue stripping. All cases were followed-up for a period of 3 years; and results were assessed according to 100 point constant score. A total of 75% cases showed excellent to good results. To minimize the complications like pin site infection, loosening, neurovascular damage we used fixed pin site insertion technique, and threaded pins in osteoporotic patients. So percutaneous pinning is a safe and novel method of management of unstable proximal humeral fractures if certain principles are borne in mind before using it.

  14. Two-Year Outcomes in Patients With Severe Aortic Valve Stenosis Randomized to Transcatheter Versus Surgical Aortic Valve Replacement

    DEFF Research Database (Denmark)

    Søndergaard, Lars; Steinbrüchel, Daniel Andreas; Ihlemann, Nikolaj

    2016-01-01

    BACKGROUND: The Nordic Aortic Valve Intervention (NOTION) trial was the first to randomize all-comers with severe native aortic valve stenosis to either transcatheter aortic valve replacement (TAVR) with the CoreValve self-expanding bioprosthesis or surgical aortic valve replacement (SAVR), inclu...... population. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01057173....

  15. Regional brain stiffness changes across the Alzheimer's disease spectrum

    Directory of Open Access Journals (Sweden)

    Matthew C. Murphy

    2016-01-01

    Full Text Available Magnetic resonance elastography (MRE is an MRI-based technique to noninvasively measure tissue stiffness. Currently well established for clinical use in the liver, MRE is increasingly being investigated to measure brain stiffness as a novel biomarker of a variety of neurological diseases. The purpose of this work was to apply a recently developed MRE pipeline to measure regional brain stiffness changes in human subjects across the Alzheimer's disease (AD spectrum, and to gain insights into the biological processes underlying those stiffness changes by correlating stiffness with existing biomarkers of AD. The results indicate that stiffness changes occur mostly in the frontal, parietal and temporal lobes, in accordance with the known topography of AD pathology. Furthermore, stiffness in those areas correlates with existing imaging biomarkers of AD including hippocampal volumes and amyloid PET. Additional analysis revealed preliminary but significant evidence that the relationship between brain stiffness and AD severity is nonlinear and non-monotonic. Given that similar relationships have been observed in functional MRI experiments, we used task-free fMRI data to test the hypothesis that brain stiffness was sensitive to structural changes associated with altered functional connectivity. The analysis revealed that brain stiffness is significantly and positively correlated with default mode network connectivity. Therefore, brain stiffness as measured by MRE has potential to provide new and essential insights into the temporal dynamics of AD, as well as the relationship between functional and structural plasticity as it relates to AD pathophysiology.

  16. Research on static angular stiffness measurement of flexible joint

    Directory of Open Access Journals (Sweden)

    Yongchao HUANG

    2016-10-01

    Full Text Available Measurement accuracy of the angular stiffness of flexible joint is directly related to the control accuracy and sensitivity of gyro, but the traditional measurement methods have many problems. According to the principle of angular stiffness measurement of flexible joint, two static measurement methods of angular stiffness are proposed based on different loading ways, namely mechanical loading angular stiffness measurement and piezoelectric loading angular stiffness measurement. The mechanical loading angular stiffness measurement system is built by using a motor driven indexing feeding tilting table, the measure experiment if the angular stiffness of flexible joint is conducted, and the angular stiffness of flexible joint is measured. For the excessive fluctuation problem of the measure result in mechanical load test, a piezoelectric loading structure is designed and a measurement method employing piezoelectric actuator is proposed for angular stiffness measurement of flexible joint. Based on ANSYS Workbench, the displacement output of the piezoelectric loading structure is analyzed by simulations. The simulation results illustrate that the displacement output meets the requirement of static loading angular stiffness measurement of flexible joint, and the theoretical feasibility of piezoelectric loading angular stiffness measurement method is validated.

  17. Early Outcomes of Acute Retrograde Dissection From the International Registry of Acute Aortic Dissection.

    Science.gov (United States)

    Nauta, Foeke J H; Kim, Joon Bum; Patel, Himanshu J; Peterson, Mark D; Eckstein, Hans-Henning; Khoynezhad, Ali; Ehrlich, Marek P; Eusanio, Marco Di; Corte, Alessandro Della; Montgomery, Daniel G; Nienaber, Christoph A; Isselbacher, Eric M; Eagle, Kim A; Sundt, Thoralf M; Trimarchi, Santi

    2017-01-01

    To provide data on the management and outcomes of patients with acute retrograde aortic dissection (AD) originating from a tear in the descending aorta with extension into the aortic arch or ascending aorta. All patients enrolled in the International Registry of Acute Aortic Dissection from 1996-2015 were reviewed. Retrograde AD was defined by primary tear in the descending aorta with proximal extension into the arch or ascending aorta. Primary end points were in-hospital management strategy and mortality. We identified 101 patients with retrograde AD (67 men; 63.2 ± 14.0 years). During index hospitalization, medical (MED), open surgical (SURG), and endovascular (ENDO) therapies were undertaken in 44, 33, and 22 patients, respectively. The SURG group presented with larger ascending aorta (P = 0.04) and more frequent ascending aortic involvement (81.8% [27/33] vs 22.7% [15/66], P < 0.001) compared with the MED and ENDO groups. Early mortality rate was 9.1% (4/44), 18.2% (6/33), and 13.6% (3/22), for the MED, SURG, and ENDO groups (P = 0.51), respectively. A favorable early mortality rate was observed in patients with retrograde extension limited to the arch (8.6% [5/58]) vs into the ascending aorta (18.6% [8/43], P = 0.14). Early mortality rate of patients with retrograde AD with primary tear in the descending aorta (12.9% [13/101]) was significantly lower than those with classic type A AD presenting with primary tear in the ascending aorta (20.0% [195/977], P = 0.001). A subset of patients with acute retrograde AD originating from primary tear in the descending aorta might be managed less invasively with acceptable early results, particularly among those with proximal extension limited to the arch. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Cosmology with a stiff matter era

    Science.gov (United States)

    Chavanis, Pierre-Henri

    2015-11-01

    We consider the possibility that the Universe is made of a dark fluid described by a quadratic equation of state P =K ρ2 , where ρ is the rest-mass density and K is a constant. The energy density ɛ =ρ c2+K ρ2 is the sum of two terms: a rest-mass term ρ c2 that mimics "dark matter" (P =0 ) and an internal energy term u =K ρ2=P that mimics a "stiff fluid" (P =ɛ ) in which the speed of sound is equal to the speed of light. In the early universe, the internal energy dominates and the dark fluid behaves as a stiff fluid (P ˜ɛ , ɛ ∝a-6). In the late universe, the rest-mass energy dominates and the dark fluid behaves as pressureless dark matter (P ≃0 , ɛ ∝a-3). We provide a simple analytical solution of the Friedmann equations for a universe undergoing a stiff matter era, a dark matter era, and a dark energy era due to the cosmological constant. This analytical solution generalizes the Einstein-de Sitter solution describing the dark matter era, and the Λ CDM model describing the dark matter era and the dark energy era. Historically, the possibility of a primordial stiff matter era first appeared in the cosmological model of Zel'dovich where the primordial universe is assumed to be made of a cold gas of baryons. A primordial stiff matter era also occurs in recent cosmological models where dark matter is made of relativistic self-gravitating Bose-Einstein condensates (BECs). When the internal energy of the dark fluid mimicking stiff matter is positive, the primordial universe is singular like in the standard big bang theory. It expands from an initial state with a vanishing scale factor and an infinite density. We consider the possibility that the internal energy of the dark fluid is negative (while, of course, its total energy density is positive), so that it mimics anti-stiff matter. This happens, for example, when the BECs have an attractive self-interaction with a negative scattering length. In that case, the primordial universe is nonsingular and

  19. Age and Aortic Diameters in Pilots.

    Science.gov (United States)

    Akın, Ahmet; Ozturk, Cengiz; Aparci, Mustafa; Cakmak, Tolga; Metin, Suleyman; Balta, Sevket; Sen, Ahmet

    2015-12-01

    Pilots are exposed to various physical and hemodynamic stresses during flight. Aortic dilatation may be one of the important consequences of flight-related stress. In this study, we evaluated whether or not variation in aortic diameter was associated with the type of aircraft and the age of pilots. Medical records of 87 jet aircraft pilots (JP) (mean age = 30.0 ± 7.0 years) and 65 non-jet aircraft pilots (NJP) (mean age = 32.63 ± 5.7) were reviewed. Echocardiographic diameters of the aortic sinus (AoS) and ascending aorta (AoAsc) were measured using standard echo probe positions. Aortic diameters were not statistically different between JP and NJP. Regression analysis revealed that the diameters of the AoS (R = 0.484, R(2) = 0.234, p age in the JP group. Whereas, there was not any relationship found between age and the diameters of the AoS and AoAsc in the NJP group. Jet pilots had aortic enlargement as they became older in contrast to the NJP group. Although the aortic diameters were not within the critical ranges in the JP group, these results could suggest that flight-related stresses might result in acute aortic syndromes in the long term. Reprint & Copyright © 2015 Association of Military Surgeons of the U.S.

  20. Ascending aortic injuries following blunt trauma.

    Science.gov (United States)

    Sun, Xiumei; Hong, Jenny; Lowery, Robert; Goldstein, Steven; Wang, Zuyue; Lindsay, Joseph; Hill, Peter C; Corso, Paul J

    2013-11-01

    The diagnosis and the management of traumatic thoracic aortic injuries have undergone significant changes due to new technology and improved prehospital care. Most of the discussions have focused on descending aortic injuries. In this review, we discuss the recent management of ascending aortic injuries. We found 5 cohort studies on traumatic aortic injuries and 11 case reports describing ascending aortic injuries between 1998 to the present through Medline research. Among case reports, 78.9% of cases were caused by motor vehicle accidents (MVA). 42.1% of patients underwent emergent open repair and the operative mortality was 12.5%. 36.8% underwent delayed repair. Associated injuries occurred in 84.2% of patients. Aortic valve injury was concurrent in 26.3% of patients. The incidence of ascending aortic injury ranged 1.9-20% in cohort studies. Traumatic injuries to the ascending aorta are relatively uncommon among survivors following blunt trauma. Aortography has been replaced by computed tomography and echocardiography as a diagnostic tool. Open repair, either emergent or delayed, remains the treatment of choice. © 2013 Wiley Periodicals, Inc.

  1. Associations of atherosclerosis in the descending thoracic aorta on CTA with arterial stiffness and chronic kidney disease in asymptomatic patients with diabetes mellitus.

    Science.gov (United States)

    Roos, Cornelis J; Delgado, V; de Koning, Eelco J; Rabelink, Ton J; Jukema, J Wouter; Bax, Jeroen J; Scholte, Arthur J

    2014-08-01

    The relation between atherosclerosis in the descending thoracic aortic (DTA), arterial stiffness and chronic kidney disease (CKD) in patients with diabetes mellitus (DM) remains unclear. The current aim was to evaluate associations of DTA atherosclerosis with arterial stiffness and parameters of CKD in asymptomatic patients with DM. A total of 213 asymptomatic patients with diabetes (mean age 52 years, 56% men) underwent cardiovascular risk assessment including multi-slice computed tomography (for non-invasive coronary angiography, from which DTA atherosclerosis can be derived), non-invasive assessment of arterial stiffness with applanation tonometry and assessment of renal function. Measurements of DTA atherosclerosis included assessment of DTA thickening and calcium score. Arterial stiffness was determined by the carotid-femoral pulse wave velocity (PWV), parameters of CKD included estimated glomerular filtration rate (eGFR) and urinary albumin-creatinine ratio (UACR). DTA atherosclerosis was present in 180 (84%) patients. Patients with DTA atherosclerosis had increased arterial stiffness, lower eGFR and higher UACR values. After multivariate correction, DTA calcium score was independently associated with PWV (β = 0.18, p = 0.04). Furthermore, both DTA maximal wall thickness and DTA calcium score were independently associated with eGFR (β = -7.37, p < 0.001 and β = -1.99, p < 0.003, respectively), but not with UACR. The increase in arterial stiffness by atherosclerosis seemed to be mediated by arterial calcification, while the DTA calcium score was independently associated with arterial stiffness, but not DTA maximal wall thickness. Furthermore, parameters of CKD in patients with DM had a distinct relationship with DTA atherosclerosis: DTA atherosclerosis was associated with eGFR but not with UACR.

  2. Mycotic Aneurysm of the Aortic Arch

    Directory of Open Access Journals (Sweden)

    Ji Hye Seo

    2014-08-01

    Full Text Available A mycotic aneurysm of the thoracic aorta is rare. We report a case of mycotic aneurysm that developed in the aortic arch. An 86-year-old man was admitted with fever and general weakness. Blood culture yielded methicillin-resistant Staphylococcus aureus. Chest X-ray showed an enlarged aortic arch, and computed tomography scan revealed an aneurysm in the aortic arch. The patient was treated only with antibiotics and not surgically. The size of the aneurysm increased rapidly, resulting in bronchial obstruction and superimposed pneumonia. The patient died of respiratory failure.

  3. Aortic histomine syntesis in experimental neurogenic hypertension.

    Science.gov (United States)

    Bolitho, G A; Hollis, T M

    1975-04-01

    Aortic histamine synthesis of normotensive rats has been compared to that of rats rendered hypertensive via production carotid sinus ischemia and to animals additionally subjected to bilateral adrenalectomy. Results indicate that the aortic histamine-forming capacities (HFC's) of rats sacrificed 24 hr after surgical treatment were elevated 83% and 103% for hypertensive rats and those additionally subjected to adrenalectomy, respectively. At an 8-day postoperative interval, the respective aortic HFC's were elevated over control by 33% and 45%, although at this time interval animals were not considered hypertensive. This study thus offers suggestive evidence that hypertension causes increased vascular permeability by increasing the histamine-forming capacity of the vessel wall.

  4. Aortic Valve Morphology Correlates With Left Ventricular Systolic Function and Outcome in Children With Congenital Aortic Stenosis Prior to Balloon Aortic Valvuloplasty.

    Science.gov (United States)

    Gao, Kevin; Sachdeva, Ritu; Goldstein, Bryan H; Lang, Sean; Petit, Christopher J

    2016-09-01

    We sought to determine the relationship between aortic valve morphology and left ventricular (LV) systolic function in children with aortic stenosis (AS) prior to balloon aortic valvuloplasty (BAV). Both aortic valve morphology and LV systolic function have been linked with outcomes in children with congenital AS undergoing BAV. The relationship between aortic valve morphology and LV function is poorly defined despite their importance in regard to outcomes. We performed a retrospective multicenter cohort study of 89 AS patients who underwent BAV between 2007-2013. Pre-BAV echocardiograms were analyzed for: aortic valve opening (AVO); aortic valve type (true bicuspid, functionally bicuspid, or unicuspid); maximal raphe length; aortic valve leaflet symmetry; and valve angle of excursion. The primary endpoint was low function, defined as LV shortening fraction (LVSF) aortic valve mean gradient was 47.00 mm Hg (IQR, 36.75-56.00 mm Hg). Multivariate analysis demonstrated that low AVO (P=.03) was associated with reduced LV function, independent of age or aortic valve gradient (R² = .652). Bicuspid aortic valve (P=.07) was associated with improved LV function compared with functionally unicuspid aortic valve. Low AVO stenosis. Qualitative aspects such as valve type may also affect LV systolic function. Further study may elucidate whether aortic valve morphology or LV function is the principal predictor of response to BAV and of late outcomes after BAV.

  5. PULSE WAVE VELOCITY AND CENTRAL AORTIC PRESSURE IN OBESE CHILDREN ACCORDING TO THE NON-INVASIVE ARTERIOGRAPHY RESULTS

    Directory of Open Access Journals (Sweden)

    O. V. Kozhevnikova

    2013-01-01

    Full Text Available The article presents information value of non-invasive arteriography, which reveals early signs of cardiovascular pathology formation in children, using a large number of trials in children. The authors examined predictors of cardiovascular catastrophes’ development, confirmed in adults: aortic wall’s stiffness, central aortic pressure and pulse pressure – that have not been sufficiently studied in children yet. The article shows that the high-technology method of non-invasive arteriography allows revealing changes of these parameters in children on the preclinical stage. It also shows their correlation with body mass index, fatty hepatosis, direct correlation of weight gain with connection of pulse wave velocity and central blood pressure and importance of follow-up evaluation of these parameters. Heterogeneity of the group of obese children in terms of these parameters is a premise for development of individual approach to control and prevention of cardiovascular complications’ development risk in childhood.

  6. Importance of stent-graft design for aortic arch aneurysm repair

    Directory of Open Access Journals (Sweden)

    C Singh

    2017-02-01

    Full Text Available Aneurysm of the aorta is currently treated by open surgical repair or endovascular repair. However, when the aneurysm occurs in regions between the aortic arch and proximal descending aorta, it can be a complex pathology to treat due to its intricate geometry. When complex aortic aneurysms are treated with the conventional procedures, some of the patients present with significant post-operative complications and high mortality rate. Consequently, a clinically driven hybrid innovation known as the frozen elephant trunk procedure was introduced to treat complex aortic aneurysms. Although this procedure significantly reduces mortality rate and operating time, it is still associated with complications such as endoleaks, spinal cord ischemia, renal failure and stroke. Some of these complications are consequences of a mismatch in the biomechanical behaviour of the stent-graft device and the aorta. Research on complex aneurysm repair tended to focus more on the surgical procedure than the stent-graft design. Current stent-graft devices are suitable for straight vessels. However, when used to treat aortic aneurysm with complex geometry, these devices are ineffective in restoring the normal biological and biomechanical function of the aorta. A stent-graft device with mechanical properties that are comparable with the aorta and aortic arch could possibly lead to fewer post-operative complications, thus, better outcome for patients with complex aneurysm conditions. This review highlights the influence stent-graft design has on the biomechanical properties of the aorta which in turn can contribute to complications of complex aneurysm repair. Design attributes critical for minimising postoperative biomechanical mismatch are also discussed.

  7. The role of aortic wall CT attenuation measurements for the diagnosis of acute aortic syndromes

    Energy Technology Data Exchange (ETDEWEB)

    Knollmann, Friedrich D., E-mail: friedrich.knollmann@ucdmc.ucdavis.edu [Department of Radiology, University of California, Davis, 4860 Y Street, Sacramento, CA 95817 (United States); Departments of Radiology and Cardiothoracic Surgery, University of Pittsburgh, 200 Lothrop Street, Pittsburgh, PA 15213 (United States); Lacomis, Joan M.; Ocak, Iclal; Gleason, Thomas [Department of Radiology, University of California, Davis, 4860 Y Street, Sacramento, CA 95817 (United States); Departments of Radiology and Cardiothoracic Surgery, University of Pittsburgh, 200 Lothrop Street, Pittsburgh, PA 15213 (United States)

    2013-12-01

    Objectives: To determine if measurements of aortic wall attenuation can improve the CT diagnosis of acute aortic syndromes. Methods: CT reports from a ten year period were searched for acute aortic syndromes (AAS). Studies with both an unenhanced and a contrast enhanced (CTA) series that had resulted in the diagnosis of intramural hematoma (IMH) were reviewed. Diagnoses were confirmed by medical records. The attenuation of aortic wall abnormalities was measured. The observed attenuation threshold was validated using studies from 39 new subjects with a variety of aortic conditions. Results: The term “aortic dissection” was identified in 1206, and IMH in 124 patients’ reports. IMH was confirmed in 31 patients, 21 of whom had both unenhanced and contrast enhanced images. All 21 had pathologic CTA findings, and no CTA with IMH was normal. Attenuation of the aortic wall was greater than 45 HUs on the CTA images in all patients with IMH. When this threshold was applied to the new group, sensitivity for diagnosing AAS was 100% (19/19), and specificity 94% (16/17). Addition of unenhanced images did not improve accuracy. Conclusions: Measurements of aortic wall attenuation in CTA have a high negative predictive value for the diagnosis of acute aortic syndromes.

  8. Aortic root reimplantation procedure: a new milestone in aortic valve-sparing operations

    Directory of Open Access Journals (Sweden)

    А. М. Чернявский

    2016-08-01

    Full Text Available Aim: Emphasis in this study was placed on clinical and functional assessment of a modified "Florida Sleeve" procedure during surgical correction of ascending aorta aneurysms with concomitant aortic insufficiency.Methods: 32 patients with an aneurysm of the ascending aorta and aortic insufficiency underwent a modified "Florida Sleeve" procedure. The average follow-up was 17 (0-60 months. The average age of patients was 57±13 (23-73 years 56±13 years.Results: The expected 4-year cumulative survival rate was 84.3%. Overall freedom from aortic insufficiency in the late period was 88.9%. Median aortic regurgitation was 1+ (1; 2. Long-term follow-up revealed no valve-associated complications.Conclusion: The aortic root reimplantation procedure enables optimal correction of the existing lesions of the aortic root without performing aortic valve replacement and demonstrates stable clinical and functional outcomes in the long-term period.Key words: aortic aneurysm; aortic valve; valve-sparing operations.FundingThe study had no sponsorship.Conflict of interestThe authors declare no conflict of interest.

  9. Circulating matrix metalloproteinase patterns in association with aortic dilatation in bicuspid aortic valve patients with isolated severe aortic stenosis.

    Science.gov (United States)

    Wang, Yongshi; Wu, Boting; Dong, Lili; Wang, Chunsheng; Wang, Xiaolin; Shu, Xianhong

    2016-02-01

    Bicuspid aortic valve (BAV) exhibits a clinical incline toward aortopathy, in which aberrant tensile and shear stress generated by BAV can induce differential expression of matrix metalloproteinases (MMPs) and their endogenous tissue inhibitors (TIMPs). Whether stenotic BAV, which exhibits additional eccentric high-velocity flow jet upon ascending aorta and further worsens circumferential systolic wall shear stress than BAV with echocardiographically normal aortic valve, can lead to unique plasma MMP/TIMP patterns is still unknown. According to their valvulopathy and aortic dilatation status, 93 BAV patients were included in the present study. Group A (n = 37) and B (n = 28) comprised severely stenotic patients with or without ascending aorta dilatation; Group C (n = 12) and D (n = 16) comprised echocardiographically normal BAV patients with or without ascending aorta dilatation. Plasma MMP/TIMP levels (MMP-1, -2, -3, -8, -9, -10, -13 and TIMP-1, -2, -4) were determined via a multiplex ELISA detection system in a single procedure. Among patients with isolated severe aortic stenosis, plasma levels of MMP-2 and -9 were significantly elevated when ascending aortic dilatation was present (p = 0.001 and p = 0.002, respectively). MMP-2, however, remained as the single elevated plasma component among echocardiographically normal BAV patients with dilated ascending aorta (p = 0.027). Multivariate analysis revealed that MMP-2 and MMP-9 could both serve as independent risk factor for aortic dilatation in the case of isolated severe stenosis (p = 0.003 and p = 0.001, respectively), and MMP-2 in echocardiographically normal patients (p = 0.002). In conclusion, BAV patients with isolated severe aortic stenosis demonstrated a distinct plasma MMP/TIMP pattern, which might be utilized as circulating biomarkers for early detection of aortic dilatation.

  10. Photoactivated In Vivo Proximity Labeling.

    Science.gov (United States)

    Beck, David B; Bonasio, Roberto

    2017-06-19

    Identification of molecular interactions is paramount to understanding how cells function. Most available technologies rely on co-purification of a protein of interest and its binding partners. Therefore, they are limited in their ability to detect low-affinity interactions and cannot be applied to proteins that localize to difficult-to-solubilize cellular compartments. In vivo proximity labeling (IPL) overcomes these obstacles by covalently tagging proteins and RNAs based on their proximity in vivo to a protein of interest. In IPL, a heterobifunctional probe comprising a photoactivatable moiety and biotin is recruited by a monomeric streptavidin tag fused to a protein of interest. Following UV irradiation, candidate interacting proteins and RNAs are covalently biotinylated with tight spatial and temporal control and subsequently recovered using biotin as an affinity handle. Here, we describe experimental protocols to discover novel protein-protein and protein-RNA interactions using IPL. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

  11. Expression of CD4+ CD28null T lymphocytes in children and adolescents with type 1 diabetes mellitus: Relation to microvascular complications, aortic elastic properties, and carotid intima media thickness.

    Science.gov (United States)

    El-Samahy, Mona H; Tantawy, Azza A G; Adly, Amira A M; Habeeb, Nevin M; Ismail, Eman A R; Hamed, Gehan M; Eladawy, Rasha

    2017-12-01

    Cardiovascular risk in type 1 diabetes mellitus (T1DM) is associated with endothelial dysfunction, inflammation, and altered immunity. CD4+ CD28null T-cells are a subset of long-lived cytotoxic CD4+ T-lymphocytes with proatherogenic and plaque-destabilizing properties. We hypothesized that the frequency of CD4+ CD28null T-cells may be altered in T1DM and related to vascular complications. To assess the percentage of CD4+ CD28null T-lymphocytes in children and adolescents with T1DM and their relation to vascular structure and glycemic control. Totally 100 patients with T1DM were divided into 2 groups according to the presence of microvascular complications and compared with 50 healthy controls. CD4+ CD28null T-lymphocytes were analyzed using flow cytometry. Aortic elastic properties and carotid intima media thickness (CIMT) were assessed. Aortic stiffness index and CIMT were significantly higher among patients compared with healthy controls while aortic strain and distensibility were decreased. The percentage of CD4+ CD28null T-cells was significantly higher in patients with and without microvascular complications compared with controls. High frequency of CD4+ CD28null T-cells was found among patients with microalbuminuria or peripheral neuropathy. Patients with CD4+ CD28null T-cells ≥10% had higher HbA1c, urinary albumin creatinine ratio, aortic stiffness, and CIMT. CD4+ CD28null T-cells were positively correlated to HbA1c, aortic stiffness index, and CIMT. Changes in aortic elastic properties and increased CIMT among young patients with T1DM may enable the recognition of preclinical cardiac impairment. The correlation between CD4+ CD28null T-cells and assessed parameters of vascular structure highlights the role of altered immune response in the occurrence of diabetic vascular complications. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Prox-1 Automated Proximity Operations

    Science.gov (United States)

    2016-01-13

    on demonstrating the functionality required to meet minimum mission success criteria. The minimum mission includes on- orbit spacecraft checkout of...also includes deployment of LightSail-B from the P-POD, and imaging of LightSail-B for 20 minutes as it recedes from Prox-1. small satellite ; proximity...criteria. The minimum mission includes on- orbit spacecraft checkout of all spacecraft subsystems, including flight qualification of the following new

  13. Thompson′s quadricepsplasty for stiff knee

    Directory of Open Access Journals (Sweden)

    Kundu Z

    2007-01-01

    Full Text Available Background : Stiffness of the knee after trauma and/or surgery for femoral fractures is one of the most common complications and is difficult to treat. Stiffness in extension is more common and can be reduced by vigorous physiotherapy. If it does not improve then quadricepsplasty is indicated. The present study was undertaken to evaluate the results of Thompsons quadricepsplasty. Materials and Methods : 22 male patients (age range 20-45 years with posttraumatic knee stiffness following distal femoral fractures underwent Thompson′s quadricepsplasty where knee flexion range was less than 45°. The index injury in these patients was treated with plaster cast (n=5, plates (n=3, intramedullary nailing (n=3 and external fixator for open fractures (n=9. Thompson′s quadricepsplasty was performed in all the patients using anterior approach, with incision extending from upper thigh to tibial tubercle. Release of rectus femoris from underlying vastus intermedius and release of intraarticular adhesions were performed. After surgery the patients needed parentral analgesia for three days and then oral analgesics for three weeks. Active assisted knee mobilization exercises were started on the first post-operative day. Continous passive motion machine was used from the same day. Supervised physiotherapy was continued in hospital for six weeks followed by intensive knee flexion and extension exercise including cycling at home for atleast another six months. Results : Out of 22 patients, 20 had excellent to good results and two patients had poor results using criteria devised by Judet. One poor result was due to peroperative fracture of patella which was then internally fixed and hence the flexion of knee could not be started immediately. There was peroperative avulsion of tibial tuberosity in another patient who finally gained less than 50° knee flexion and hence a poor result. Conclusion : Thompsons quadricepsplasty followed by a strict and rigourous

  14. Vibration Control via Stiffness Switching of Magnetostrictive Transducers

    Science.gov (United States)

    Scheidler, Justin J.; Asnani, Vivake M.; Dapino, Marcelo J.

    2016-01-01

    This paper presents a computational study of structural vibration control that is realized by switching a magnetostrictive transducer between high and low stiffness states. Switching is accomplished by either changing the applied magnetic field with a voltage excitation or changing the shunt impedance on the transducer's coil (i.e., the magnetostrictive material's magnetic boundary condition). Switched-stiffness vibration control is simulated using a lumped mass supported by a damper and the magnetostrictive transducer (mount), which is represented by a nonlinear, electromechanical model. Free vibration of the mass is calculated while varying the mount's stiffness according to a reference switched-stiffness vibration control law. The results reveal that switching the magnetic field produces the desired change in stiffness, but also an undesired actuation force that can significantly degrade the vibration control. Hence, a modified switched-stiffness control law that accounts for the actuation force is proposed and implemented for voltage-controlled stiffness switching. The influence of the magnetomechanical bias condition is also discussed. Voltage-controlled stiffness switching is found to introduce damping equivalent to a viscous damping factor up to about 0.25; this is shown to primarily result from active vibration reduction caused by the actuation force. The merit of magnetostrictive switched-stiffness vibration control is then quantified by comparing the results of voltage- and shunt-controlled stiffness switching to the performance of optimal magnetostrictive shunt damping.

  15. Biomechanical response to ankle-foot orthosis stiffness during running.

    Science.gov (United States)

    Russell Esposito, Elizabeth; Choi, Harmony S; Owens, Johnny G; Blanck, Ryan V; Wilken, Jason M

    2015-12-01

    The Intrepid Dynamic Exoskeletal Orthosis (IDEO) is an ankle-foot orthosis developed to address the high rates of delayed amputation in the military. Its use has enabled many wounded Service Members to run again. During running, stiffness is thought to influence an orthosis' energy storage and return mechanical properties. This study examined the effect of orthosis stiffness on running biomechanics in patients with lower limb impairments who had undergone unilateral limb salvage. Ten patients with lower limb impairments underwent gait analysis at a self-selected running velocity. 1. Nominal (clinically-prescribed), 2. Stiff (20% stiffer than nominal), and 3. Compliant (20% less stiff than nominal) ankle-foot orthosis stiffnesses were tested. Ankle joint stiffness was greatest in the stiffest strut and lowest in the compliant strut, however ankle mechanical work remained unchanged. Speed, stride length, cycle time, joint angles, moments, powers, and ground reaction forces were not significantly different among stiffness conditions. Ankle joint kinematics and ankle, knee and hip kinetics were different between limbs. Ankle power, in particular, was lower in the injured limb. Ankle-foot orthosis stiffness affected ankle joint stiffness but did not influence other biomechanical parameters of running in individuals with unilateral limb salvage. Foot strike asymmetries may have influenced the kinetics of running. Therefore, a range of stiffness may be clinically appropriate when prescribing ankle-foot orthoses for active individuals with limb salvage. Published by Elsevier Ltd.

  16. MEMS Variable Stiffness Spring and Its Application in Fuze

    Directory of Open Access Journals (Sweden)

    Li Sui

    2014-04-01

    Full Text Available MEMS processing technology can manufacture any complex structures in a plane, using this point, a variable stiffness design idea for the planar micro-spring is proposed. That is, using one type of structure named contact pairs to achieve stiffness change during the micro-spring’s stretching process. Using contact pairs, three types of variable stiffness springs are designed: stiffness increase spring, stiffness decrease spring and stiffness hump spring. Finally, the variable stiffness springs’ application for fuze setback arming device is discussed. When the three types of springs are used in setback arming device, the stiffness decrease spring is better than the other two springs from security analysis. Kinematic analysis shows that, if the variable stiffness spring’s design is reasonable, the setback arming device not only can effectively solve the safety and reliability issues for rocket fuze, but also applies in small caliber grenade fuze’s working environment without changing the setback arming device’s size and structure. Analysis result indicate that the setback arming device based on MEMS variable stiffness spring is universal for rocket fuze and small caliber grenade fuze.

  17. Prosthetic mitral inflow mimicking severe aortic regurgitation (revisited). An echocardiographic challenge.

    Science.gov (United States)

    Battisha, Ayman; Abdelhaleem, Ahmed; Srialluri, Swetha; Arisha, Mohammed J; Farhoud, Adel A; Kamel, Hassan; Mahmoud, Mohamed S; Tageldin, Omar; Salama, Ahmed Y; Ibeche, Bashar; Nanda, Navin C

    2017-10-01

    Assessing aortic regurgitation (AR) severity in patients with mitral valve prosthesis may pose an echocardiographic challenge. We present a case of mild AR in whom difficulty occurred in judging its severity due to eccentric mitral prosthetic inflow signals filling practically completely the proximal left ventricular outflow tract in diastole mimicking severe AR. Frame-by-frame analysis of two-dimensional transthoracic echocardiographic images using a small sector depth and width was helpful in clarifying the true severity of AR. © 2017, Wiley Periodicals, Inc.

  18. Acute aortic dissection: An update

    Directory of Open Access Journals (Sweden)

    Iván Alejandro De León Ayala

    2012-06-01

    Full Text Available The aorta, which has a complex intrinsic biology and sophisticated mechanical properties for conducting the blood ejected from the left ventricle to the rest of the systemic arterial bed, is the largest and strongest artery in the body. It carries roughly 200 million liters of blood in an average lifetime. Any process that undermines the architecture threatens the structure, stability, and functionality of the aorta. In this regard, acute aortic dissection (AAD requires special attention because it is the most catastrophic acute illness of the aorta; it has high morbidity and mortality because of potentially fatal complications. AAD has, therefore, become an important topic of recent research, and knowledge about this disease has improved during the past few years. Up-to-date knowledge about the natural history, epidemiology, presentation, physiopathology, evolution, management, follow-up, and long-term outcomes of AAD are summarized in this review.

  19. How to estimate aortic characteristic impedance from magnetic resonance and applanation tonometry data?

    Science.gov (United States)

    Bollache, Emilie; Kachenoura, Nadjia; Bargiotas, Ioannis; Giron, Alain; De Cesare, Alain; Bensalah, Mourad; Lucor, Didier; Redheuil, Alban; Mousseaux, Elie

    2015-03-01

    Compare seven previous methods for the estimation of aortic characteristic impedance, which contributes to left ventricle pulsatile load, from phase-contrast cardiovascular magnetic resonance (CMR) and applanation tonometry data. We studied 77 healthy (43 ± 16 years) individuals and 16 hypertensive (61 ± 9 years) patients, who consecutively underwent ascending aorta CMR and carotid tonometry, resulting in flow and pressure waveforms, respectively. Characteristic impedance was semi-automatically estimated in time domain from these latter waveforms, using seven methods. The methods were based on the following: methods 1-4, magnitudes at specific times; method 5, early-systolic up-slope; method 6, time-derivatives peak; and method 7, pressure-flow loop early-systolic slope. Aortic characteristic impedance was significantly increased in hypertensive patients when compared to elderly controls (n = 32) with a similar mean age of (59 ± 8 years) when using methods based on 95% of peak flow, up-slopes, and derivatives peaks (P characteristic impedance was correlated to the frequency-domain reference values (r > 0.65, P  0.82, P characteristic impedance temporal estimation. Methods based on 95% of peak flow, as well as those based on derivative peaks and up-slopes, which are fast and independent of curve preprocessing, were slightly superior. They can be easily integrated in a clinical workflow and may help to understand the complementarity of this pulsatile index with other CMR aortic geometry and stiffness measures in the setting of left ventricle-aortic coupling.

  20. Predictive value of platelet-to-lymphocyte ratio in severe degenerative aortic valve stenosis

    Directory of Open Access Journals (Sweden)

    Efe Edem

    2016-01-01

    Full Text Available Background: Aortic valve stenosis (AVS is the most common cause of left ventricular outflow obstruction, and its prevalence among elderly patients causes a major public health burden. Recently, platelet-to-lymphocyte ratio (PLR has been recognized as a novel prognostic biomarker that offers information about both aggregation and inflammation pathways. Since PLR indicates inflammation, we hypothesized that PLR may be associated with the severity of AVS due to chronic inflammation pathways that cause stiffness and calcification of the aortic valve. Materials and Methods: We retrospectively enrolled 117 patients with severe degenerative AVS, who underwent aortic valve replacement and 117 control patients in our clinic. PLR was defined as the absolute platelet count divided by the absolute lymphocyte count. Severe AVS was defined as calcification and sclerosis of the valve with a mean pressure gradient of >40 mmHg. Results: PLR was 197.03 ± 49.61 in the AVS group and 144.9 ± 40.35 in the control group, which indicated a statistically significant difference (P < 0.001. A receiver operating characteristic (ROC curve analysis demonstrated that PLR values over 188 predicted the severity of aortic stenosis with a sensitivity of 87% and a specificity of 70% (95% confidence interval = 0.734–0.882; P < 0.001; area under ROC curve: 0.808. Conclusion: We suggest that the level of PLR elevation is related to the severity of degenerative AVS, and PLR should be used to monitor patients' inflammatory responses and the efficacy of treatment, which will lead us to more closely monitor this high-risk population to detect severe degenerative AVS at an early stage.

  1. Vertical Dynamic Stiffness of Offshore Foundations

    DEFF Research Database (Denmark)

    Latini, Chiara; Cisternino, Michele; Zania, Varvara

    2016-01-01

    Nowadays, pile and suction caisson foundations are widely used to support offshore structures which are subjected to vertical dynamic loads. The dynamic soil-structure interaction of floating foundations (foundations embedded in a soil layer whose height is greater than the foundation length......) is investigated by numerical analyses of representative finite element models. The 3D numerical model is compared and validated with existing analytical solutions. A parametric study is carried out analyzing the effect of the slenderness ratio Hp/d and the height and the stiffness of the soil layer on the dynamic...

  2. Aortic root reoperations after pulmonary autograft implantation

    NARCIS (Netherlands)

    J.A. Bekkers (Jos); L.M.A. Klieverik (Loes Maria Anne); G. Bol-Raap (Goris); J.J.M. Takkenberg (Hanneke); A.J.J.C. Bogers (Ad)

    2010-01-01

    textabstractObjective: To report the results of aortic root reoperations after pulmonary autograft implantation. Methods: All consecutive patients in our prospective Ross research database were selected for analysis, and additional information for patients requiring reoperation was obtained from the

  3. Aortic Distensibility in β-Thalassemia Major

    Directory of Open Access Journals (Sweden)

    A Aslani

    2008-11-01

    Full Text Available Background: Any unfavorable effect of β-Thalassemia major on aortic distensibility will contribute to the adverseeffects of β-Thalassemia major on the cardiovascular system. To evaluated aortic distensibility in patients with β-Thalassemia major. Patients and Methods: The study comprised eighty (46 males consecutive β-Thalassemia major patients and 80 control subjects matched for age and gender were selected. Results: Aortic distensibility was approximately two-fold lower in patients compared with control subjects [aorticdistensibility: 1.4 ± 0.8 vs 3.6 ± 1.2, cm2 dyn-1 10-6, P = 0.01. Conclusion: β-Thalassemia major causes significant decrease in aortic distensibility.

  4. Minimally Invasive Transcatheter Aortic Valve Replacement (TAVR)

    Medline Plus

    Full Text Available Watch a Broward Health surgeon perform a minimally invasive Transcatheter Aortic Valve Replacement (TAVR) Click Here to view the BroadcastMed, Inc. Privacy Policy and Legal Notice © 2017 BroadcastMed, Inc. All rights reserved.

  5. Traumatic aortic dissection presenting with respiratory arrest

    Directory of Open Access Journals (Sweden)

    C.C. Meyer

    2015-03-01

    Conclusion: Blunt aortic injury is a major cause of death in blunt chest trauma. Signs and symptoms of this injury are nonspecific and other injuries often take precedence, which makes a relatively difficult diagnosis even more challenging.

  6. Endoluminal treatment of thoracic aortic lesions

    African Journals Online (AJOL)

    Enrique

    20 The predominant predictors ... age, chronic obstructive pulmonary disease and an elevated mean blood pressure increase the risk of ... disease, dissection or aortic rupture require immediate diagnostic evalua- tion and pre-procedural ...

  7. Dissecting aortic aneurysm in maintenance hemodialysis patients

    Directory of Open Access Journals (Sweden)

    Ounissi M

    2009-01-01

    Full Text Available The dissecting aortic aneurysm (DAA is a rare pathology that may result in fatal outcome. We report follow up of three cases of DAA patients undergoing maintenance hemo-dialysis who were managed conservatively.

  8. [Asymptomatic severe aortic stenosis: a reopened debate].

    Science.gov (United States)

    Urso, Stefano; Sadaba, Rafael; de la Cruz, Elena

    2014-05-06

    Aortic stenosis is a complex disease. About 2-7% of the population over 65 years of age is affected by its degenerative form. In patients with severe aortic stenosis presenting with symptoms or left ventricle ejection fraction (LVEF)debate. Recent published data show that about one third of these patients present with low left ventricle stroke volume, which may affect survival. For this reason, and considering that aortic valve replacement is in most cases a low risk procedure, early surgery in this subgroup is a strategy that deserves to be taken into account. In this review we report on these recent findings, which allow understanding why patients with asymptomatic severe aortic stenosis should not be considered and treated as a homogenous population. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  9. Minimally Invasive Transcatheter Aortic Valve Replacement (TAVR)

    Medline Plus

    Full Text Available Watch a Broward Health surgeon perform a minimally invasive Transcatheter Aortic Valve Replacement (TAVR) Click Here to view the BroadcastMed, Inc. Privacy Policy and Legal Notice © 2017 BroadcastMed, Inc. ...

  10. Management of acute type B aortic dissection.

    Science.gov (United States)

    Hughes, G Chad; Andersen, Nicholas D; McCann, Richard L

    2013-03-01

    Acute type B aortic dissection (identified within 2 weeks of symptom onset), as described using the Stanford classification, involves the aorta distal to the left subclavian artery and accounts for 25%-40% of all aortic dissections. The traditional treatment paradigm of medical management for uncomplicated acute type B dissection and open surgical intervention for early or late complications of type B dissection is currently undergoing a period of evolution as a result of the influence of minimally invasive thoracic endovascular aortic repair options. Thoracic endovascular repair has replaced open surgical repair as the preferred treatment for complicated acute type B dissection, and may also prove beneficial for prophylactic repair of uncomplicated acute type B dissection for high-risk patients. This review discusses the management of acute type B aortic dissection and long-term treatment considerations. Copyright © 2013 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  11. Successful Thrombolysis of Aortic Prosthetic Valve Thrombosis ...

    African Journals Online (AJOL)

    Arun Kumar Agnihotri

    threatening. Standard surgical treatment using cardiopulmonary bypass carries high maternal and fetal complications. Here we report a case of an antenatal female in first trimester with aortic prosthetic valve thrombosis (PVT), who was successfully ...

  12. Infective endocarditis following transcatheter aortic valve replacement-

    DEFF Research Database (Denmark)

    Loh, Poay Huan; Bundgaard, Henning; S�ndergaard, Lars

    2013-01-01

    Transcatheter aortic valve replacement (TAVR) can improve the symptoms and prognosis of patients with severe aortic stenosis who, due to a high expected operative risk, would not have otherwise been treated surgically. If these patients develop prosthetic valve endocarditis, their presentations m...... treated medically, discuss the challenges in the diagnosis and management of such patients, and review available literature on the incidence and outcome of the condition. © 2012 Wiley Periodicals, Inc....

  13. Preliminary Evidence for Aortopathy and an X-Linked Parent-of-Origin Effect on Aortic Valve Malformation in a Mouse Model of Turner Syndrome

    Directory of Open Access Journals (Sweden)

    Robert B. Hinton

    2015-07-01

    Full Text Available Turner syndrome (TS, most frequently caused by X-monosomy (45,X, is characterized in part by cardiovascular abnormalities, including aortopathy and bicuspid aortic valve (BAV. There is a need for animal models that recapitulate the cardiovascular manifestations of TS. Extracellular matrix (ECM organization and morphometrics of the aortic valve and proximal aorta were examined in adult 39,XO mice (where the parental origin of the single X was paternal (39,XPO or maternal (39,XMO and 40,XX controls. Aortic valve morphology was normal (tricuspid in all of the 39,XPO and 40,XX mice studied, but abnormal (bicuspid or quadricuspid in 15% of 39,XMO mice. Smooth muscle cell orientation in the ascending aorta was abnormal in all 39,XPO and 39,XMO mice examined, but smooth muscle actin was decreased in 39,XMO mice only. Aortic dilation was present with reduced penetrance in 39,XO mice. The 39,XO mouse demonstrates aortopathy and an X-linked parent-of-origin effect on aortic valve malformation, and the candidate gene FAM9B is polymorphically expressed in control and diseased human aortic valves. The 39,XO mouse model may be valuable for examining the mechanisms underlying the cardiovascular findings in TS, and suggest there are important genetic modifiers on the X chromosome that modulate risk for nonsyndromic BAV and aortopathy.

  14. Síndrome stiff skin: relato de caso Stiff skin syndrome: case report

    Directory of Open Access Journals (Sweden)

    Adriana Gutstein da Fonseca Amorim

    2011-08-01

    Full Text Available Síndrome stiff skin é doença rara, esclerodermiforme, de etiologia desconhecida, caracterizada por endurecimento pétreo da pele, hipertricose leve e limitação da mobilidade articular. Não há tratamento efetivo até o momento. Exercícios e reabilitação são importantes para manter a qualidade de vida do paciente. Os autores apresentam caso de um menino de dois anos de idade com endurecimento cutâneo progressivo desde os oito meses de idade e restrição secundária da mobilidade articular, diagnosticado como Síndrome stiff skinStiff skin syndrome is a rare scleroderma-like disorder of unknown etiology characterized by stone-hard indurations of skin, mild hypertrichosis and limited joint mobility. No effective treatment has yet been found. Exercises and rehabilitative therapy are important in maintaining the patient's quality of life. The authors present a case of a two-year-old boy with progressive skin hardening since he was eightmonth old and secondary restricted joint mobility, diagnosed as Stiff skin syndrome

  15. Aortic Dissection Type A in Alpine Skiers

    Directory of Open Access Journals (Sweden)

    Thomas Schachner

    2013-01-01

    Full Text Available Patients and Methods. 140 patients with aortic dissection type A were admitted for cardiac surgery. Seventy-seven patients experienced their dissection in the winter season (from November to April. We analyzed cases of ascending aortic dissection associated with alpine skiing. Results. In 17 patients we found skiing-related aortic dissections. Skiers were taller (180 (172–200 cm versus 175 (157–191 cm, and heavier (90 (68–125 kg versus 80 (45–110 kg, than nonskiers. An extension of aortic dissection into the aortic arch, the descending thoracic aorta, and the abdominal aorta was found in 91%, 74%, and 69%, respectively, with no significant difference between skiers and nonskiers. Skiers experienced RCA ostium dissection requiring CABG in 17.6% while this was true for 5% of nonskiers (. Hospital mortality of skiers was 6% versus 13% in nonskiers (. The skiers live at an altitude of 170 (0–853 m.a.s.l. and experience their dissection at 1602 (1185–3105; m.a.s.l. In 82% symptom start was during recreational skiing without any trauma. Conclusion. Skiing associated aortic dissection type A is usually nontraumatic. The persons affected live at low altitudes and practice an outdoor sport at unusual high altitude at cold temperatures. Postoperative outcome is good.

  16. Aortic Dissection Type A in Alpine Skiers

    Science.gov (United States)

    Schachner, Thomas; Fischler, Nikolaus; Dumfarth, Julia; Bonaros, Nikolaos; Krapf, Christoph; Schobersberger, Wolfgang; Grimm, Michael

    2013-01-01

    Patients and Methods. 140 patients with aortic dissection type A were admitted for cardiac surgery. Seventy-seven patients experienced their dissection in the winter season (from November to April). We analyzed cases of ascending aortic dissection associated with alpine skiing. Results. In 17 patients we found skiing-related aortic dissections. Skiers were taller (180 (172–200) cm versus 175 (157–191) cm, P = 0.008) and heavier (90 (68–125) kg versus 80 (45–110) kg, P = 0.002) than nonskiers. An extension of aortic dissection into the aortic arch, the descending thoracic aorta, and the abdominal aorta was found in 91%, 74%, and 69%, respectively, with no significant difference between skiers and nonskiers. Skiers experienced RCA ostium dissection requiring CABG in 17.6% while this was true for 5% of nonskiers (P = 0.086). Hospital mortality of skiers was 6% versus 13% in nonskiers (P = 0.399). The skiers live at an altitude of 170 (0–853) m.a.s.l. and experience their dissection at 1602 (1185–3105; P skiing without any trauma. Conclusion. Skiing associated aortic dissection type A is usually nontraumatic. The persons affected live at low altitudes and practice an outdoor sport at unusual high altitude at cold temperatures. Postoperative outcome is good. PMID:23971024

  17. Changes in Central Aortic Pressure Levels, Wave Components and Determinants Associated with High Peripheral Blood Pressure States in Childhood: Analysis of Hypertensive Phenotype.

    Science.gov (United States)

    García-Espinosa, Victoria; Curcio, Santiago; Marotta, Marco; Castro, Juan M; Arana, Maite; Peluso, Gonzalo; Chiesa, Pedro; Giachetto, Gustavo; Bia, Daniel; Zócalo, Yanina

    2016-10-01

    The aims were to determine whether children's high peripheral blood pressure states (HBP) are associated with increased central aortic blood pressure (BP) and to characterize hemodynamic and vascular changes associated with HBP in terms of changes in cardiac output (stroke volume, SV), arterial stiffness (aortic pulse wave velocity, PWV), peripheral vascular resistances (PVR) and net and relative contributions of reflected waves to the aortic pulse amplitude. We included 154 subjects (mean age 11; range 4-16 years) assigned to one of two groups: normal peripheral BP (NBP, n = 101), defined as systolic and diastolic BP wave-derived parameters (augmentation index, forward and backward wave components' amplitude) were measured using gold-standard techniques, applanation tonometry (SphygmoCor) and oscillometry (Mobil-O-Graph). Independent of the presence of dyslipidemia and/or obesity, aortic systolic and pulse BP were higher in HBP than in NBP children. The increase in central BP could not be explained by an increase in the relative contribution of reflections to the aortic pressure wave, higher PVR or by an augmented peripheral reflection coefficient. Instead, the rise in central BP would be explained by an increase in the amplitude of both incident and reflected wave components.

  18. Elastic metamaterial beam with remotely tunable stiffness

    Science.gov (United States)

    Qian, Wei; Yu, Zhengyue; Wang, Xiaole; Lai, Yun; Yellen, Benjamin B.

    2016-02-01

    We demonstrate a dynamically tunable elastic metamaterial, which employs remote magnetic force to adjust its vibration absorption properties. The 1D metamaterial is constructed from a flat aluminum beam milled with a linear array of cylindrical holes. The beam is backed by a thin elastic membrane, on which thin disk-shaped permanent magnets are mounted. When excited by a shaker, the beam motion is tracked by a Laser Doppler Vibrometer, which conducts point by point scanning of the vibrating element. Elastic waves are unable to propagate through the beam when the driving frequency excites the first elastic bending mode in the unit cell. At these frequencies, the effective mass density of the unit cell becomes negative, which induces an exponentially decaying evanescent wave. Due to the non-linear elastic properties of the membrane, the effective stiffness of the unit cell can be tuned with an external magnetic force from nearby solenoids. Measurements of the linear and cubic static stiffness terms of the membrane are in excellent agreement with experimental measurements of the bandgap shift as a function of the applied force. In this implementation, bandgap shifts by as much as 40% can be achieved with ˜30 mN of applied magnetic force. This structure has potential for extension in 2D and 3D, providing a general approach for building dynamically tunable elastic metamaterials for applications in lensing and guiding elastic waves.

  19. STIFF: Converting Scientific FITS Images to TIFF

    Science.gov (United States)

    Bertin, Emmanuel

    2011-10-01

    STIFF is a program that converts scientific FITS1 images to the more popular TIFF2 format for illustration purposes. Most FITS readers and converters do not do a proper job at converting FITS image data to 8 bits. 8-bit images stored in JPEG, PNG or TIFF files have the intensities implicitely stored in a non-linear way. Most current FITS image viewers and converters provide the user an incorrect translation of the FITS image content by simply rescaling linearly input pixel values. A first consequence is that the people working on astronomical images usually have to apply narrow intensity cuts or square-root or logarithmic intensity transformations to actually see something on their deep-sky images. A less obvious consequence is that colors obtained by combining images processed this way are not consistent across such a large range of surface brightnesses. Though with other software the user is generally afforded a choice of nonlinear transformations to apply in order to make the faint stuff stand out more clearly in the images, with the limited selection of choices provides, colors will not be accurately rendered, and some manual tweaking will be necessary. The purpose of STIFF is to produce beautiful pictures in an automatic and consistent way.

  20. Elastic metamaterial beam with remotely tunable stiffness

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Wei [University of Michigan–Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai 200240 (China); Yu, Zhengyue [School of Naval Architecture, Ocean & Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Wang, Xiaole [School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Lai, Yun [College of Physics, Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Yellen, Benjamin B., E-mail: yellen@duke.edu [University of Michigan–Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai 200240 (China); Department of Mechanical Engineering and Materials Science, Duke University, P.O. Box 90300, Hudson Hall, Durham, North Carolina 27708 (United States)

    2016-02-07

    We demonstrate a dynamically tunable elastic metamaterial, which employs remote magnetic force to adjust its vibration absorption properties. The 1D metamaterial is constructed from a flat aluminum beam milled with a linear array of cylindrical holes. The beam is backed by a thin elastic membrane, on which thin disk-shaped permanent magnets are mounted. When excited by a shaker, the beam motion is tracked by a Laser Doppler Vibrometer, which conducts point by point scanning of the vibrating element. Elastic waves are unable to propagate through the beam when the driving frequency excites the first elastic bending mode in the unit cell. At these frequencies, the effective mass density of the unit cell becomes negative, which induces an exponentially decaying evanescent wave. Due to the non-linear elastic properties of the membrane, the effective stiffness of the unit cell can be tuned with an external magnetic force from nearby solenoids. Measurements of the linear and cubic static stiffness terms of the membrane are in excellent agreement with experimental measurements of the bandgap shift as a function of the applied force. In this implementation, bandgap shifts by as much as 40% can be achieved with ∼30 mN of applied magnetic force. This structure has potential for extension in 2D and 3D, providing a general approach for building dynamically tunable elastic metamaterials for applications in lensing and guiding elastic waves.

  1. Stiffness Evolution in Frozen Sands Subjected to Stress Changes

    KAUST Repository

    Dai, Sheng

    2017-04-21

    Sampling affects all soils, including frozen soils and hydrate-bearing sediments. The authors monitor the stiffness evolution of frozen sands subjected to various temperature and stress conditions using an oedometer cell instrumented with P-wave transducers. Experimental results show the stress-dependent stiffness of freshly remolded sands, the dominant stiffening effect of ice, creep after unloading, and the associated exponential decrease in stiffness with time. The characteristic time for stiffness loss during creep is of the order of tens of minutes; therefore it is inevitable that frozen soils experience sampling disturbances attributable to unloading. Slow unloading minimizes stiffness loss; conversely, fast unloading causes a pronounced reduction in stiffness probably attributable to the brittle failure of ice or ice-mineral bonding.

  2. PROXIMATE AND ELEMENTAL COMPOSITION OF WHITE GRUBS

    African Journals Online (AJOL)

    DR. AMINU

    PROXIMATE AND ELEMENTAL COMPOSITION OF WHITE GRUBS. 1 Alhassan, A. J. 1M .S. Sule, 1J. ... ABSTRACT. This study determined the proximate and mineral element composition of whole white grubs using standard methods of analysis. Proximate ... days, before pulverized to powder and kept in plastic container.

  3. Ambulatory arterial stiffness index and its role in assessing arterial stiffness in dialysis patients.

    Science.gov (United States)

    Liu, Wenjin; Zhou, Jiajun; Chen, Jianping; Meng, Meijuan; Li, Xiurong; Gao, Chaoqing; Zhou, Jianmei; Wang, Liang; Sun, Zhuxing; Chu, Hong; Fan, Wei; Bai, Youwei; Yang, Junwei

    2017-06-01

    Ambulatory arterial stiffness index (AASI) is a parameter derived from ambulatory blood pressure (ABP) readings. It is calculated as 1 minus the linear slope of DBP on SBP. We tested its value in assessing arterial stiffness in dialysis patients. We performed a cross-sectional analysis of the baseline data from a cohort study. A total of 344 patients on maintenance hemodialysis from six tertiary hospitals were included. All patients underwent ABP monitoring and carotid-femoral pulse wave velocity (cfPWV) measurement. Clinical determinants of AASI were analyzed, and the ability of AASI for assessing arterial stiffness was compared with ambulatory pulse pressure (PP). Multiple regression analysis revealed that ambulatory PP (β = 0.003), current smoker (β = -0.069), age (β = 0.003) and ambulatory SBP (β = 0.001) were independent determinants of AASI. Ambulatory PP correlates better with cfPWV than AASI (r = 0.28 for AASI and 0.59 for PP; P for difference: <0.001). When cfPWV was treated as a categorical variable, receiver operating characteristic curve analysis also showed a more potent predictive value of PP over AASI (area under the curve: 0.64 for AASI, 0.80 for PP; P for difference: <0.001). Net reclassification improvement and integrated discrimination improvement analysis demonstrated no added predictive value of AASI to PP (net reclassification improvement = -2.2%, P = 0.26; integrated discrimination improvement = 0.001, P = 0.51). Sensitivity analysis in patients with more ABP readings (≥49) yielded similar results. For dialysis patients, AASI has very limited value in assessing arterial stiffness, whether used alone or added to PP. Our results suggest that this index should not be used as a surrogate marker of arterial stiffness for dialysis patients in future practice and studies.

  4. Infantile Aortic Coarctation in an Adult with Heart Failure.

    Science.gov (United States)

    Rumiz, Eva; Valero, Ernesto; Vilar, Juan Vicente; Santas, Enrique; Haba, Javier

    2017-01-01

    The aim of this case report is to highlight the importance of excluding aortic coarctation in a patient with a bicuspid aortic valve. A 56-year-old woman with hypertension was admitted complaining of progressive dyspnea. Transthoracic echocardiography showed a calcified, bicuspid aortic valve with severe stenosis. Aortography revealed the presence of severe narrowing of the aorta between the carotid and subclavian arteries. The patient was referred for cardiovascular surgery in which successful aortic valve replacement and aortic correction were performed. This case report shows an uncommon finding of infantile aortic coarctation in an adult patient admitted with heart failure. © 2016 S. Karger AG, Basel.

  5. Arterial stiffness, hypertension, and rational use of nebivolol

    Directory of Open Access Journals (Sweden)

    Enrico Agabiti-Rosei

    2009-05-01

    Full Text Available Enrico Agabiti-Rosei, Enzo Porteri, Damiano RizzoniClinica Medica, Department of Medical and Surgical Sciences, University of Brescia, ItalyAbstract: Arterial stiffness plays a key role in the pathophysiology of the cardiovascular system. Some indices of arterial stiffness (pulse wave velocity, augmentation index, characteristics of central blood pressure waveform may be presently calculated and evaluated in the clinical setting. Age and blood pressure are the two major clinical determinants of increased arterial stiffness, while molecular determinants of arterial stiffness are related to fibrotic components of the extracellular matrix, mainly elastin, collagen and fibronectin. Increased arterial stiffness has been consistently observed in conditions such as hypertension, dyslipidemia and diabetes. Arterial stiffness evaluated by means of carotid-femoral pulse wave velocity yielded prognostic significance beyond and above traditional risk factors. A more favorable effect of calcium channel blockers, diuretics and ACE inhibitors compared with β-blockers on indices of arterial stiffness was observed in several studies. It is conceivable that newer β-blockers with additional vasodilating properties, such as nebivolol, which has favorable effects on carbohydrate and lipid metabolism, as well as on endothelial function and on oxidative stress, may have favorable effects on arterial stiffness, compared with atenolol. In fact, in recent studies, nebivolol was demonstrated to improve artery stiffness to a greater extent than older β-blockers. Because endothelial dysfunction and increased arterial stiffness play an important role in the early atherosclerotic processes and are associated with poor outcomes and increased mortality, independently of blood pressure, the ability of nebivolol to enhance release of endothelium-derived nitric oxide, and consequently improve endothelial function and arterial stiffness, may have significant clinical

  6. Quantification of Magnetically Induced Changes in ECM Local Apparent Stiffness

    OpenAIRE

    Herath, Sahan C.B.; Yue, Du; Hui, Shi; Kim, Min-Cheol; Wang, Dong-An; Wang, Qingguo; Van Vliet, Krystyn J.; Asada, Harry; Chen, Peter C.Y.

    2014-01-01

    The stiffness of the extracellular matrix (ECM) is known to influence cell behavior. The ability to manipulate the stiffness of ECM has important implications in understanding how cells interact mechanically with their microenvironment. This article describes an approach to manipulating the stiffness ECM, whereby magnetic beads are embedded in the ECM through bioconjugation between the streptavidin-coated beads and the collagen fibers and then manipulated by an external magnetic field. It als...

  7. Biomechanical effects of calcar screws and bone block augmentation on medial support in locked plating of proximal humeral fractures.

    Science.gov (United States)

    Katthagen, Jan Christoph; Schwarze, Michael; Meyer-Kobbe, Josefin; Voigt, Christine; Hurschler, Christof; Lill, Helmut

    2014-08-01

    The objective of this study was to investigate the biomechanical effects of medial fracture gap augmentation in locked plating of an unstable 2-part proximal humeral fracture with calcar screws and insertion of a corticocancellous bone block. Furthermore the mechanical behavior of dynamic locking screws in the non-parallel arrangement of a proximal humeral plate was of interest. Thirty-two fresh frozen humeri were randomized in four equal groups. An unstable 2-part fracture was fixed by locked plating in all specimens. The basic screw setup was supplemented by additional calcar screws in one group. Humeral head screws were replaced by dynamic locking screws in a second group. The third group featured an additional corticocancellous femoral head allograft. Assessment of stiffness was followed by cyclic loading and load to failure tests. Resulting stiffness, fracture gap deflection and ultimate load were compared utilizing Bonferroni corrected t-test for independent samples. The mechanical effect of additional calcar screws was non-significant as compared to the basic screw configuration whereas bone block insertion significantly increased construct stiffness and failure load. The use of dynamic locking screws did not significantly reduce construct stiffness when compared to conventional locking screws. Additional calcar screws alone did not improve the initial biomechanical properties of an unstable 2-part proximal humeral fracture model. However bone block augmentation appeared to be a reliable alternative of additional bony support by raising stiffness and failure load. Dynamic locking screws did not show their expected dynamic component when used in a non-parallel arrangement. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Aorta measurements are heritable and influenced by bicuspid aortic valve

    Directory of Open Access Journals (Sweden)

    Lisa J Martin

    2011-09-01

    Full Text Available Abstract: Word Count 266, 1609 charactersObjectives: To determine whether the contributions of genetics and bicuspid aortic valve (BAV independently influence aortic (Ao dimensions.Background: Ao dilation is a risk factor for aneurysm, dissection, and sudden cardiac death. Frequent association of BAV with Ao dilation implicates a common underlying defect possibly due to genetic factors. Methods: Families enriched for BAV underwent standardized transthoracic echocardiography. In addition to BAV status, echocardiographic measures of Ao (annulus to descending Ao, pulmonary artery and mitral valve annulus diameters were obtained. Using variance components analysis, heritability was estimated with and without BAV status. Additionally, bivariate genetic analyses between Ao dimensions and BAV were performed.Results: Our cohort was obtained from 209 families enriched for BAV. After adjusting for age, body surface area and sex, individuals with BAV had a statistically significant increase in all echocardiographic measurements (p < 0.006 except descending Ao and mitral valve annulus. Individuals with BAV were at greater odds of having Ao dilation (OR = 4.44, 95% CI 2.93 – 6.72 than family members without BAV. All echocardiographic measurements exhibited moderate to strong heritability (0.25 to 0.53, and these estimates were not influenced by inclusion of BAV as a covariate. Bivariate genetic analyses supported that the genetic correlation between BAV and echo measures were not significantly different from zero.Conclusions: We show for the first time that echocardiographic measurements of Ao, pulmonary artery and mitral valve annulus diameters are quantitative traits that exhibit significant heritability. In addition, our results suggest the presence of BAV independently influences the proximal Ao and pulmonary artery measures but not those in the descending Ao or mitral valve annulus.

  9. Aortic Valve and Thoracic Aortic Calcification Measurements : How Low Can We Go in Radiation Dose?

    NARCIS (Netherlands)

    van Hamersvelt, Robbert Willem; den Harder, Annemarie M; Willemink, Martin J; Schilham, Arnold M R|info:eu-repo/dai/nl/239678605; Lammers, Jan-Willem J|info:eu-repo/dai/nl/071697624; Nathoe, Hendrik M|info:eu-repo/dai/nl/267961472; Budde, Ricardo P J; Leiner, Tim; de Jong, Pim A|info:eu-repo/dai/nl/287955672

    OBJECTIVE: This study aimed to determine the lowest radiation dose and iterative reconstruction level(s) at which computed tomography (CT)-based quantification of aortic valve calcification (AVC) and thoracic aortic calcification (TAC) is still feasible. METHODS: Twenty-eight patients underwent a

  10. General Considerations of Ruptured Abdominal Aortic Aneurysm: Ruptured Abdominal Aortic Aneurysm

    OpenAIRE

    Lee, Chung Won; Bae, Miju; Chung, Sung Woon

    2015-01-01

    Although development of surgical technique and critical care, ruptured abdominal aortic aneurysm still carries a high mortality. In order to obtain good results, various efforts have been attempted. This paper reviews initial management of ruptured abdominal aortic aneurysm and discuss the key point open surgical repair and endovascular aneurysm repair.

  11. Transcatheter Aortic Valve Replacement With Early- and New-Generation Devices in Bicuspid Aortic Valve Stenosis

    DEFF Research Database (Denmark)

    Yoon, Sung Han; Lefèvre, Thierry; Ahn, Jung Ming

    2016-01-01

    Background Few studies have evaluated the clinical outcomes of transcatheter aortic valve replacement (TAVR) in patients with bicuspid aortic valve stenosis (AS). Particularly, limited data exist comparing the results of TAVR with new-generation devices versus early-generation devices.  Objective...

  12. Outcomes of thoracic endovascular aortic repair in adult coarctation patients.

    Science.gov (United States)

    Lala, Salim; Scali, Salvatore T; Feezor, Robert J; Chandrekashar, Satish; Giles, Kristina A; Fatima, Javairiah; Berceli, Scott A; Back, Martin R; Huber, Thomas S; Beaver, Thomas M; Beck, Adam W

    2017-09-22

    Aortic coarctation (AC) is most commonly identified in pediatric patients; however, adults can present with late sequelae of untreated coarctation or complications of prior open repair. To date, there are limited data about the role of thoracic endovascular aortic repair (TEVAR) in this group of patients. The purpose of this analysis was to describe our experience with management of adult coarctation patients using TEVAR. All TEVAR patients treated for primary coarctation or late sequelae of previous open repair (eg, pseudoaneurysm, recurrent coarctation or anastomotic stenosis related to index open coarctation repair) were reviewed. Demographics, comorbidities, procedure-related variables, postoperative outcomes, and reintervention were recorded. Computed tomography centerline assessments of endograft morphology were completed to delineate stent anatomy at the coarctation site. Survival and reintervention were estimated using life-table analysis. A total of 21 patients were identified (median age, 46 years [range, 33-71 years]; 67% male [n = 14]). Nine patients (43%) were treated for symptomatic primary (n = 6) or recurrent (n = 3) coarctation. Other indications included degenerative thoracic aneurysm (n = 6), pseudoaneurysm (n = 4), and dissection (n = 2). Technical success was 100% (95% confidence interval [CI], 84%-100%). No 30-day mortality or paraplegia events occurred; however, two patients (10%) experienced postoperative nondisabling stroke. In primary or recurrent coarctation patients with available computed tomography imaging (n = 8 of 9), nominal stent graft diameters were achieved proximal and distal to the coarctation (range, -0.4 to -1.2 mm of desired final stent diameter). Specific to the coarctation site, there was a significant increase in aortic diameter after TEVAR (before stenting, 11.5 [95% CI, 6.8-12.3] mm; after stenting, 15 [95% CI, 13.7-15.7] mm; P = .004). Concurrently, systolic arterial blood pressure at time of discharge was

  13. Synthesis of stiffness and mass matrices from experimental vibration modes.

    Science.gov (United States)

    Ross, R. G., Jr.

    1971-01-01

    With highly complex structures, it is sometimes desirable to derive a dynamic model of the system from experimental vibration data. This paper presents algorithms for synthesizing the mass and stiffness matrices from experimentally derived modal data in a way which preserves the physical significance of the individual mass and stiffness elements. The synthesizing procedures allow for the incorporation of other mass and stiffness data, whether empirical or based on the analyst's insight. The mass and stiffness matrices are derived for a cantilever beam example and are compared with those obtained using earlier techniques.

  14. Variable stiffness mechanisms of dual parameters changing magnetorheological fluid devices

    Science.gov (United States)

    Deng, Huaxia; Wang, Mingxian; Han, Guanghui; Zhang, Jin; Ma, Mengchao; Zhong, Xiang; Yu, Liandong

    2017-12-01

    Magnetorheological fluid (MRF) dampers are widely used as the variable damping devices in the semi-active vibration control system. In order to further improve the vibration reduction performance, a variable stiffness MRF damper with two chambers and two springs has been proposed recently. According to the test results, both of the damping and stiffness of the device can be controllable by changing the applied current independently. However, the mechanisms of variable stiffness for this device are still not clear. In this paper, the force transmissions of the parts of the variable stiffness MRF damper are analyzed, which reveals the variable stiffness mechanisms of dual parameters changing MRF devices. There are three stages for the variable stiffness MRF damper due to the friction and the yield of MR fluid. These stages can be controlled by the applied current of the different chambers, which changes the equivalent stiffness of the device. The proposed modelling of the device is verified by simulations and tests. In addition, the relationships between the equivalent stiffness and the parameters of the device are derived, which provide the design guidance for the variable stiffness MRF dampers.

  15. Nonlinear stiffness profiles of external fixators constructed with composite rods.

    Science.gov (United States)

    Carlson, Kimberly R; Kraus, Karl H; Kowaleski, Michael P

    2006-12-01

    To determine if composite connecting rods confer nonlinear stiffness characteristics on unilateral and bilateral external skeletal fixators (ESF) in cranial-caudal bending and axial loading. Mechanical testing performed on models. Six models of 6-pin ESF constructs composed of birch dowels, a commercial ESF system, and composite connecting rods. Unilateral and bilateral ESF configurations were assembled using either specially designed composite titanium and silicone (composite group) or solid titanium (solid group) connecting rods. Mechanical testing was performed in axial loading and 4-point cranial-caudal bending. Stiffness was determined at a low and high-load range, and was considered increasing and nonlinear if the stiffness at high loads was greater than at low loads. The stiffness of the solid group was linear in all testing modes and configurations. Bilateral composite fixators had a nonlinear increasing stiffness in axial loading and cranial-caudal bending. Unilateral composite fixators had a nonlinear increasing stiffness in axial loading, but not cranial-caudal bending. Solid connecting rods conferred a higher stiffness in all testing modes and configurations. Composite connecting rods resulted in nonlinear increasing axial and bending stiffness in bilateral fixators, and in axial load in unilateral fixators. Conventional ESF can be constructed so that the stiffness increases as load increases. This provides the surgeon with additional options to control the local mechanical environment of a healing fracture, which may be used to enhance fracture healing.

  16. A novel variable stiffness mechanism for dielectric elastomer actuators

    Science.gov (United States)

    Li, Wen-Bo; Zhang, Wen-Ming; Zou, Hong-Xiang; Peng, Zhi-Ke; Meng, Guang

    2017-08-01

    In this paper, a novel variable stiffness mechanism is proposed for the design of a variable stiffness dielectric elastomer actuator (VSDEA) which combines a flexible strip with a DEA in a dielectric elastomer minimum energy structure. The DEA induces an analog tuning of the transverse curvature of the strip, thus conveniently providing a voltage-controllable flexural rigidity. The VSDEA tends to be a fully flexible and compact structure with the advantages of simplicity and fast response. Both experimental and theoretical investigations are carried out to reveal the variable stiffness performances of the VSDEA. The effect of the clamped location on the bending stiffness of the VSDEA is analyzed, and then effects of the lengths, the loading points and the applied voltages on the bending stiffness are experimentally investigated. An analytical model is developed to verify the availability of this variable stiffness mechanism, and the theoretical results demonstrate that the bending stiffness of the VSDEA decreases as the applied voltage increases, which agree well with the experimental data. Moreover, the experimental results show that the maximum change of the relative stiffness can reach about 88.80%. It can be useful for the design and optimization of active variable stiffness structures and DEAs for soft robots, vibration control, and morphing applications.

  17. NON-INVASIVE PULSE WAVE ANALYSIS IN A THROMBUS-FREE ABDOMINAL AORTIC ANEURYSM AFTER IMPLANTATION OF A NITINOL AORTIC ENDOGRAFT.

    Directory of Open Access Journals (Sweden)

    Efstratios eGeorgakarakos

    2016-01-01

    Full Text Available Endovascular Aneurysm Repair has been associated with changes in arterial stiffness, as estimated by pulse wave velocity (PWV. This marker is influenced by the medical status of the patient, the elastic characteristics of the aneurysm wall and the intraluminal thrombus. Therefore, in order to delineate the influence of the endograft implantation in the early postoperative period, we conducted non-invasively pulse wave analysis in a male patient with an abdominal aortic aneurysm of no intraluminal thrombus, no medical history and absence of peripheral arterial disease. Central systolic and diastolic pressure decreased postoperatively. PWV showed subtle changes from 11.6m/sec to 10.6 and 10.9 at 1-week and 1-month, respectively. Accordingly, the augmentation index decreased from 28% to 14% and continued to drop to 25%. The augmentation pressure decreased gradually from 15- to 6- and 4mmHg. The wave reflection magnitude dropped from 68% to 52% at 1-month. Finally, the peripheral resistance dropped from 1.41 to 0.99 and 0.85 dyn×sec×cm−5. Our example shows that the implantation of an aortic endograft can modify the wave reflection in aorta without causing significant alterations in PWV.

  18. Abdominal Aortic Diameter Is Increased in Males with a Family History of Abdominal Aortic Aneurysms

    DEFF Research Database (Denmark)

    Mejnert Jørgensen, Trine; Houlind, K; Green, A

    2014-01-01

    measurement of maximum antero-posterior aortic diameter. Family history obtained by questionnaire. Multivariate regression analysis was used to test for confounders: age, sex, smoking, comorbidity and medication. RESULTS: From the screened cohort, 569 participants had at least one first degree relative......OBJECTIVE: To investigate, at a population level, whether a family history of abdominal aortic aneurysm (AAA) is independently related to increased aortic diameter and prevalence of AAA in men, and to elucidate whether the mean aortic diameter and the prevalence of AAA are different between...... participants with male and female relatives with AAA. DESIGN: Observational population-based cross-sectional study. MATERIALS: 18,614 male participants screened for AAA in the VIVA-trial 2008-2011 with information on both family history of AAA and maximal aortic diameter. METHODS: Standardized ultrasound scan...

  19. Combined surgical and catheter-based treatment of extensive thoracic aortic aneurysm and aortic valve stenosis

    DEFF Research Database (Denmark)

    De Backer, Ole; Lönn, Lars; Søndergaard, Lars

    2015-01-01

    valve stenosis (AS) who are considered at high risk for surgical aortic valve replacement. In this report, we describe the combined surgical and catheter-based treatment of an extensive TAA and AS. To our knowledge, this is the first report of hybrid TAA repair combined with TAVR.......An extensive thoracic aortic aneurysm (TAA) is a potentially life-threatening condition and remains a technical challenge to surgeons. Over the past decade, repair of aortic arch aneurysms has been accomplished using both hybrid (open and endovascular) and totally endovascular techniques. Thoracic...... endovascular aneurysm repair (TEVAR) has changed and extended management options in thoracic aorta disease, including in those patients deemed unfit or unsuitable for open surgery. Accordingly, transcatheter aortic valve replacement (TAVR) is increasingly used to treat patients with symptomatic severe aortic...

  20. Finger Proximal Interphalangeal Joint Dislocation.

    Science.gov (United States)

    Ramponi, Denise; Cerepani, Mary Jo

    2015-01-01

    Finger dislocations are common injuries that are often managed by emergency nurse practitioners. A systematic physical examination following these injuries is imperative to avoid complications. Radiographic views, including the anteroposterior, lateral, and oblique views, are imperative to evaluate these finger dislocations. A dorsal dislocation of the proximal interphalangeal (PIP) joint is the most common finger dislocation type often easily reduced. A volar PIP dislocation can often be difficult to reduce and may result in finger deformity. Finger dislocations should be reduced promptly. Referral to an orthopedic hand specialist is required if the dislocation is unable to be reduced or if the finger joint is unstable following reduction attempts.

  1. Equilibrium properties of proximity effect

    Energy Technology Data Exchange (ETDEWEB)

    Esteve, D.; Pothier, H.; Gueron, S.; Birge, N.O.; Devoret, M.

    1996-12-31

    The proximity effect in diffusive normal-superconducting (NS) nano-structures is described by the Usadel equations for the electron pair correlations. We show that these equations obey a variational principle with a potential which generalizes the Ginzburg-Landau energy functional. We discuss simple examples of NS circuits using this formalism. In order to test the theoretical predictions of the Usadel equations, we have measured the density of states as a function of energy on a long N wire in contact with a S wire at one end, at different distances from the NS interface. (authors). 12 refs.

  2. Proximal tendon-prosthesis junction for active tendon implants of the hand: a biomechanical comparison of 2 techniques.

    Science.gov (United States)

    Thompson, Matthew J; Owen, John R; McDowell, Charles L; Wayne, Jennifer S

    2015-01-01

    To study the biomechanical characteristics (percent stretch, stiffness, and ultimate load) of 2 tendon-prosthesis techniques used to connect the proximal tendon stump to silicone active tendon implants used in reconstruction of flexor tendons. We evaluated percent stretch following cyclic loading and at failure, stiffness during load to failure, and ultimate load of 16 tendon-prosthesis junctions using cadaveric canine flexor digitorum profundus tendons to re-create 2 junction techniques: the tendon loop (TL) and the polyester weave (PW). The TL junction showed greater percent stretch at a static load of 2 N, following 500 cycles of loading between 2 N and 50 N, and at peak load. The PW junction displayed greater stiffness from 50 to 150 N during load to failure. Both junctions failed at a mean ultimate load greater than 220 N. The described proximal junction techniques for active tendon implants were strong enough to resist early active motion in the immediate postoperative period without significant elongation. The PW technique displayed greater stiffness and ultimate load compared with the TL. Data on tendon-prosthesis characteristics of these 2 methods may aid the surgeon in choosing which junction technique to use, during surgical tensioning decisions, and in considering activity protocols after surgery. These data may also serve as a baseline for further investigations regarding active tendon implants. Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  3. Concomitant mitral regurgitation and aortic stenosis: one step further to low-flow preserved ejection fraction aortic stenosis.

    Science.gov (United States)

    Benfari, Giovanni; Clavel, Marie-Annick; Nistri, Stefano; Maffeis, Caterina; Vassanelli, Corrado; Enriquez-Sarano, Maurice; Rossi, Andrea

    2017-07-27

    Patients with severe aortic stenosis (AS) and normal ejection fraction (EF) can paradoxically present low-transaortic flow and worse prognosis. The role of co-existing mitral regurgitation (MR) in determining this haemodynamic inconsistency has never been quantitatively explored. The hypothesis is that MR influences forward stroke volume and characterizes the low-flow AS pattern. Consecutive patients with indexed aortic valve area (AVA) ≤0.6 cm2/m2 and EF > 50% formed the study population. Complete echocardiographic data were collected, and mitral effective regurgitant orifice area (ERO) and regurgitant volume were obtained with proximal isovelocity surface area method. Patients were divided into subgroups according to indexed stroke volume (SV index). Included patients were 273 [age 79 ± 10 years, 53% female, EF 65 ± 7%, indexed AVA 0.47 ± 0.09 cm2/m2, mean transaortic gradient (MG) 32 ± 17 mmHg]. Mitral regurgitation was present in 89 (32%); ERO was 0.12 ± 0.08 cm2 (range 0.02-0.49 cm2). A low-flow state (SV index ≤35 mL/m2) was diagnosed in 41 (15%) patients. The prevalence of MR was higher in with low-flow vs. normal-flow group (56 vs. 28%, P = 0.03). Effective regurgitant orifice was associated to low-flow state univariately (OR: 1.75 [1.59-2.60]; P = 0.004) and after comprehensive adjustment (OR:1.76 [1.12-2.75]; P = 0.01). When MG was forced in the model, ERO remained significant (P flow condition. Furthermore, MR quantification by ERO predicts the presence of reduced flow independently of chamber volumes, systolic function, and transaortic gradient.

  4. Hyperthyroidism affects arterial stiffness, plasma NT-pro-B-type natriuretic peptide levels, and subendocardial perfusion in patients with Graves' disease.

    Science.gov (United States)

    Bodlaj, Gerd; Pichler, Robert; Brandstätter, Walter; Hatzl-Griesenhofer, Margit; Maschek, Wilhelmine; Biesenbach, Georg; Berg, Jörg

    2007-01-01

    Arterial stiffness is thought to play a critical role in the pathogenesis of cardiovascular events, and in hyperthyroidism increased cardiovascular event rates have been reported. To investigate markers of systemic arterial stiffness, volume homeostasis, and subendocardial perfusion and its interrelationship in patients with Graves' disease (GD) in hyperthyroidism and euthyroidism. Aortic augmentation index (AIx@75) as a measure of systemic arterial stiffness and subendocardial viability ratio (SEVR) as a surrogate measure of subendocardial perfusion were assessed by applanation tonometry in 59 patients with GD in hyperthyroidism and euthyroidism, and measurements were compared to plasma levels of NT-pro-B-type natriuretic peptide (NT-ProBNP). AIx@75 and NT-ProBNP levels were significantly increased in hyperthyroidism compared to euthyroidism and were positively correlated with each other. SEVR was significantly decreased in hyperthyroidism compared to euthyroidism, mainly due to increased heart rates as shown by the heart rate-corrected SEVR75. In hyperthyroidism, patients with GD exhibited increased systemic arterial stiffness, paralleled by increased levels of NT-ProBNP, a marker of volume overload. The decreased subendocardial perfusion in hyperthyroidism seemed to be mainly due to increased heart rates. The observed unfavorable hemodynamic alterations in hyperthyroidism may serve to explain increased cardiovascular event rates in patients with GD.

  5. Visceral and renal tissue oxygenation during supraceliac aortic crossclamping and left heart bypass with selective organ perfusion.

    Science.gov (United States)

    Idu, M M; Heintjes, R J; Scholten, E W; Balm, R; de Mol, B A J M; Legemate, D A

    2004-02-01

    Left-heart bypass (LHB) and selective organ perfusion (SOP) are used during thoracoabdominal aortic surgery to prevent ischemic damage to the kidneys and visceral organs after supraceliac aortic crossclamping. We studied the hypothesis, in a porcine model, that despite LHB and maximal SOP, visceral and renal ischemia still occurred during surgery. Eleven pigs (54-70 kg) were coupled to a non-pulsatile LHB with inflow and outflow at the lower thoracic and distal infrarenal aorta, respectively. After supracoeliac and infrarenal aortic crossclamping, SOP was started using perfusion catheters. The proximal and distal mean aortic blood pressures were kept above 70 and 50 mmHg, respectively, while the mean blood pressure within the SOP system was above 60 mmHg. The visceral and renal tissue oxygenation was measured by intermittent blood gas analysis, from the portal and both renal veins. The jejunal mucosal oxygenation was measured by tonometric measurement of the luminal pCO2. Measured median blood blood flow through the LHB and the SOP system were 800 and 1140 ml/min, respectively. Median blood flow prior to, and during LHB and SOP through the celiac artery, superior mesenteric artery, and left renal artery were 300 and 240, 762 and 295, and 235 and 235 ml/min, respectively. During 3 h of LHB and SOP no significant changes in the renal tissue oxygenation were noted compared with the physiological situation prior to supracoeliac aortic crossclamping and cannulation. However, in the visceral vascular bed median mixed venous oxygen saturation dropped from 79 to 63% (p0.05). During 3 h of LHB and SOP no hemolysis was detected, as there was no rise in serum LDH. LHB and SOP preserves renal but not visceral tissue oxygenation during supraceliac aortic crossclamping and does not induce hemolysis.

  6. Early evaluation of precise deployment with the new low profile Zenith Alpha Thoracic Endoprosthesis in thoracic aortic disease.

    Science.gov (United States)

    Pane, Bianca; Spinella, Giovanni; Perfumo, Maria C; Musio, Debora; Mambrini, Simone; Ferrero, Cesare; Gazzola, Valerio; Palombo, Domenico

    2016-04-21

    Endovascular treatment of thoracic aortic disease currently allows to treat high risk patients with better results than open repair. It represents the first option for treatment according to the most recent guidelines. The aim of the study is to evaluate the early results of the low profile Zenith Alpha Thoracic Endoprosthesis (ZATE). Between October 2012 and July 2015, 14 asymptomatic patients were treated with ZATE. 10 patients were male, mean age was 71, 7 years (range 58 - 85 years). 8 patients presented with atherosclerotic aortic aneurysm (7 thoracic aneurysm and 1 type I thoracoabdominal aneurysm), 2 chronic type B aortic dissection, 1 type IV endoleak 5 years after TEVAR, 3 aortic arch penetrating ulcer complicated by pseudoaneurysm. Hybrid staged procedures in 11 patients included 7 total aortic arch debranching (1 single (innominate) chimney stent graft + Carotid-Carotid-Subclavian), 2 carotid-carotid-subclavian artery bypass, 2 carotid- subclavian artery bypass. No 30-day mortality or major complications were observed. The mean length of stay was 7.3 days (range 4-14 days). Mean procedure time, X ray time and Contrast load were 115 min (range 90-150 min), 20 min (range 10-30) and 79 mL (range 40-120 mL) respectively. 25 stent grafts were implanted. The mean follow up was 21 months (range 14 - 32 months). No mortality and no major complications were observed during the follow-up. In case of arch debranching with landing 0 and 1 zone the mean distance between the beginning of the endoprosthesis and the debranching inflow vessel was 5.5 mm (±2.4 mm) CONCLUSIONS: The use of ZATE could be a viable alternative for treating patients with aortic arch proximal landing zone to facilitate the precise deployment. Larger case studies and longer follow-up are needed.

  7. Three-dimensional finite volume modelling of blood flow in simulated angular neck abdominal aortic aneurysm

    Science.gov (United States)

    Algabri, Y. A.; Rookkapan, S.; Chatpun, S.

    2017-09-01

    An abdominal aortic aneurysm (AAA) is considered a deadly cardiovascular disease that defined as a focal dilation of blood artery. The healthy aorta size is between 15 and 24 mm based on gender, bodyweight, and age. When the diameter increased to 30 mm or more, the rupture can occur if it is kept growing or untreated. Moreover, the proximal angular neck of aneurysm is categorized as a significant morphological feature with prime harmful effects on endovascular aneurysm repair (EVAR). Flow pattern in pathological vessel can influence the vascular intervention. The aim of this study is to investigate the blood flow behaviours in angular neck abdominal aortic aneurysm with simulated geometry based on patient’s information using computational fluid dynamics (CFD). The 3D angular neck AAA models have been designed by using SolidWorks Software. Consequently, CFD tools are used for simulating these 3D models of angular neck AAA in ANSYS FLUENT Software. Eventually, based on the results, we summarized that the CFD techniques have shown high performance in explaining and investigating the flow patterns for angular neck abdominal aortic aneurysm.

  8. Experimental Model of Saccular Abdominal Aortic Aneurysm in Swines with Pericardium Sac

    Directory of Open Access Journals (Sweden)

    Maurício de Amorim Aquino

    2016-02-01

    Full Text Available Abstract Objective: To consider modifications in an experimental model of saccular aortic aneurysm, aiming at better reproducibility, to be used in the development of vascular prostheses. Methods: Experimental study in two phases, developed in the Center of Experimental Surgery and Bioterium (CCEB of the University of Health Sciences of Alagoas (UNCISAL, with 11 hybrid swine, female, mean weight of 20 ± 5 kg, according to modifications in the Perini technique was performed. In the first phase, the aneurysm was confectioned with bovine pericardial patch. In the second phase, fifteen days later, the patency of the aneurysms was confirmed by Doppler ultrasonography. The described variables were aortic and aneurysm sac patency, incidence of rupture, morbidity and mortality. The statistical analysis program used was STATA v.8. Results: All animals survived to the procedures. Surgical mean time was 73 minutes. Aneurysm rupture, proximal or distal aortic thrombosis, visceral or legs ischemia weren't observed. Parietal thrombus formation was observed in all of the aneurysms, two of which (18%; IC 95% = 3.98 - 48.84 were occluded and nine (82%; IC 95% = 51.15 - 96.01 were patent. Conclusion: In this series, the modifications carried out in the technique related to the surgical approach, race, anesthesia, and imaging exams reproduced the experimental model, reducing its costs, without hindering the analysis of the variables. The satisfactory patency ratio allows the method to be used in experimental models for the development of vascular prostheses.

  9. Stiffness control of balance in quiet standing.

    Science.gov (United States)

    Winter, D A; Patla, A E; Prince, F; Ishac, M; Gielo-Perczak, K

    1998-09-01

    Our goal was to provide some insights into how the CNS controls and maintains an upright standing posture, which is an integral part of activities of daily living. Although researchers have used simple performance measures of maintenance of this posture quite effectively in clinical decision making, the mechanisms and control principles involved have not been clear. We propose a relatively simple control scheme for regulation of upright posture that provides almost instantaneous corrective response and reduces the operating demands on the CNS. The analytic model is derived and experimentally validated. A stiffness model was developed for quiet standing. The model assumes that muscles act as springs to cause the center-of-pressure (COP) to move in phase with the center-of-mass (COM) as the body sways about some desired position. In the sagittal plane this stiffness control exists at the ankle plantarflexors, in the frontal plane by the hip abductors/adductors. On the basis of observations that the COP-COM error signal continuously oscillates, it is evident that the inverted pendulum model is severely underdamped, approaching the undamped condition. The spectrum of this error signal is seen to match that of a tuned mass, spring, damper system, and a curve fit of this "tuned circuit" yields omega n the undamped natural frequency of the system. The effective stiffness of the system, Ke, is then estimated from Ke = I omega n2, and the damping B is estimated from B = BW X I, where BW is the bandwidth of the tuned response (in rad/s), and I is the moment of inertia of the body about the ankle joint. Ten adult subjects were assessed while standing quietly at three stance widths: 50% hip-to-hip distance, 100 and 150%. Subjects stood for 2 min in each position with eyes open; the 100% stance width was repeated with eyes closed. In all trials and in both planes, the COP oscillated virtually in phase (within 6 ms) with COM, which was predicted by a simple 0th order spring

  10. Discrete computational mechanics for stiff phenomena

    KAUST Repository

    Michels, Dominik L.

    2016-11-28

    Many natural phenomena which occur in the realm of visual computing and computational physics, like the dynamics of cloth, fibers, fluids, and solids as well as collision scenarios are described by stiff Hamiltonian equations of motion, i.e. differential equations whose solution spectra simultaneously contain extremely high and low frequencies. This usually impedes the development of physically accurate and at the same time efficient integration algorithms. We present a straightforward computationally oriented introduction to advanced concepts from classical mechanics. We provide an easy to understand step-by-step introduction from variational principles over the Euler-Lagrange formalism and the Legendre transformation to Hamiltonian mechanics. Based on such solid theoretical foundations, we study the underlying geometric structure of Hamiltonian systems as well as their discrete counterparts in order to develop sophisticated structure preserving integration algorithms to efficiently perform high fidelity simulations.

  11. Effect of exercise on arterial stiffness

    DEFF Research Database (Denmark)

    Montero, David; Breenfeldt Andersen, Andreas; Oberholzer, Laura

    2017-01-01

    ), in 9 previously untrained healthy normotensive adults (27 ± 4 years) with no history of cardiovascular disease. Exercise capacity was assessed by maximal oxygen consumption (VO2max) elicited by incremental ergometry. RESULTS: VO2max increased throughout the ET intervention (+12% from week 0 to week 8......BACKGROUND: Whether arterial stiffness (AS) can be improved by regular exercise in healthy individuals remains equivocal according to cross-sectional and longitudinal studies assessing arterial properties at discrete time points. The purpose of the present study was to pinpoint the time course...... points (P = 0.196) although a linear decreasing trend was detected (P = 0.016). CONCLUSIONS: Central AS augments during a conventional ET intervention that effectively enhances aerobic exercise capacity in young individuals. This suggests that normal, healthy elastic arteries are not amendable...

  12. Vibration Control via Stiffness Switching of Magnetostrictive Transducers

    Science.gov (United States)

    Scheidler, Justin J.; Asnani, Vivake M.; Dapino, Marcelo J.

    2016-01-01

    In this paper, a computational study is presented of structural vibration control that is realized by switching a magnetostrictive transducer between high and low stiffness states. Switching is accomplished by either changing the applied magnetic field with a voltage excitation or changing the shunt impedance on the transducer's coil (i.e., the magnetostrictive material's magnetic boundary condition). Switched-stiffness vibration control is simulated using a lumped mass supported by a damper and the magnetostrictive transducer (mount), which is represented by a nonlinear, electromechanical model. Free vibration of the mass is calculated while varying the mount's stiffness according to a reference switched-stiffness vibration control law. The results reveal that switching the magnetic field produces the desired change in s